LECTURE Introduction to Programming Logic and Technique DTNhung – NIIT HAIPHONG.
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Transcript of LECTURE Introduction to Programming Logic and Technique DTNhung – NIIT HAIPHONG.
LECTURELECTURE
Introduction to Programming Logic and TechniqueIntroduction to Programming Logic and Technique
DTNhung – NIIT HAIPHONGDTNhung – NIIT HAIPHONG
22Hai Phong Software ParkHai Phong Software ParkNIITNIIT
Start-up
1. Can you list a serial generation language programming?
2. The vocabulary of commonly spoken communication is ________ the vocabulary of a programming language?a. Greater than b. Less than c. Equal to
3. What programming language do you like?
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Solutions
1. Generations of programming languages 1st generation is machine language. 2nd generation is assembly language. 3rd generation is high-level languages such
as BASIC, Pascal, C…
2. a. Greater than
3. Suggestions: Assembly, Pascal, C, C++, Visual Basic, Visual C++, Java, Delphi, ASP, JSP, Pearl…
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Introduction to Programming Logic and TechniqueIntroduction to Programming Logic and Technique
Chapter 1 Introducing to Programming Concept
Chapter 2 Representing the logic of Programming using Pseudocodes.
Chapter 3 Representing the logic of Programming using Flowcharts
Chapter 4 Understanding Iterations and Implementing Modular
Programming
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Introducing to Programming Concept
Computer follows an I-P-O cycle. It needs set of instructions called program to specify the input required, process to be followed, and the output required.
Program is written in a specific language called Programming language, so that computer can understand the instructions.
Process
Input
Output
Feedback
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A set of instructions to perform a particular job is called a program. Therefore, for each job that you want the computer to perform, you require a separate program. Instructions in a program can be:
Sequential: Instructions that are executed one after the other. „Decision Making: Instructions that evaluate an expression (relation or condition) first and then, depending upon whether the value of the expression is 'true' (non-zero) or 'false' (zero), it transfers the control to a particular statement. „ Iterative: Instructions that are executed repeatedly, depending on the value of an expression (relation or condition)
Introducing to Programming Concepts
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Programming Languages MACHINE LANGUAGE A sequence of 0s and 1s can be used to
describe any physical operation that the computer performs. Therefore, a computer system uses a number system that consists of only two digits, 0 and 1. This number system is known as the binary number system.
The language that the computer understands is called the machine language.
It is doubtful if you would be comfortable writing a program in machine language. It is certainly difficult for anybody to remember instructions in the form of 0s and 1s.
Command Machine code
ADD 00000001
SUBTRACT 00000010
MULTIPLY 00000100
DIVIDE 00001000
READ FROM KEYBOARD
00010000
WRITE ON SCREEN
00100000
WRITE ON PRINTER
01000000
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1000 010 11 1
01100101 011
0001 0 1 010 1
The binary number system uses the base of 2. For example, 101 in the binary system is equal to 5 in the decimal system. The conversion can be done as:
101=1*22 + 0*21+ 1* 20 =1*4 + 0*2 + 1*1 = 4 + 0 + 1=5
Machine language
No need translater (compiler)
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Assembly language
In the above program: The line number one loads register Ax with the value, 9. The line number two loads register Bx with the value, 10. The line number three adds the value of register Bx to the value of register Ax. The line number four stores the value of register Ax in the main memory
location, 100. The line number five uses JMP to jump to register Bx to transfer the control to
register Bx. The line number six stops the program execution.
LD Ax, 9 LD Bx, 10 ADD Ax,Bx LD (100),Ax JMP Bx HLT
Assembler100 0 00
11 11 000 0 0 1 00 0 111
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A high-level programming language consists of a set of instructions, which are represented using simple English words. So, when you want the computer to display the output on the screen, you type the instruction ‘WRITE ON SCREEN’ and not ‘00100000’.
There are many high-level programming languages available, such as C, C++, and Java. Each language has its own advantages.
Programming languages also have a vocabulary, which is referred to as the set of keywords of that language, and a grammar, which is referred to as the syntax.
High level language
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As stated earlier, a program written in any programming language is a set of logically related instructions. These instructions have two parts, as shown in the following figure:
The two parts of a programming language instruction are: „ Operation code (opcode): This part instructs a computer about the operation
to be performed. „ Operand: This part instructs the computer about the location of the data on
which the operation specified by the opcode is to be performed.
For example, in the instruction Add A and B, Add is the opcode and A and B are operands
High level language
Operation code (Opcode)
Operand(Address)
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High level language
beginnumeric nNumber1, nNumber2, nNumber3nNumber1 = 15nNumber2 = 2nNumber3 =nNumber1% nNumber2display nNumber3
end
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Algorithm
An algorithm is a sequence of steps required to solve a problem An algorithm follows the I-P-O cycle to solve the problem.
The two levels of algorithm are:
Macro-level: An algorithm that contains brief steps about a process is called a macro-level algorithm.
Micro-level: An algorithm that contains detailed steps about a process is called a micro-level algorithm.
An algorithm is represented using tools such as:
Pseudocode
Flowcharts
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Algorithm
An algorithm has the following five characteristics: An algorithm ends after a fixed number of steps. Each step in an algorithm clearly specifies the action to be
performed. The steps in an algorithm specify basic operations. These
operations could include calculations, input/output operations, and comparisons.
An algorithm accepts input data, in a defined format, before it can be processed.
An algorithm generates one or more outputs after the input is processed. The resultant information termed as output can be displayed or stored for future reference.
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Pseudocode
VocabularyDeclare (variables, literals, procedures,
functions…): khai báoAssign: gán giá trịFunction: hàmProcedure: thủ tụcFlowchart: lược đồ thuật toán Pseudocode /sj:udoucode/: mã giảVariable: biếnConstant/literal: hằngExpression: biểu thức
• Operator
Arithmetic: toán tử toán học
Relational: toán tử quan hệ
Logical: toán tử logic
• Operand: toán hạng
• Precedence: mức ưu tiên
• Comment: chú thích
• Dry run table: chạy thô
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Algorithm - PseudocodeBegin
numeric nNum1, nResult
numeric nCons = 10
Display ‘Enter the first number’
Accept nNum1
nResult = (nNum1 * nCons) / 73
If nResult > nCons
Display “ the number is greater than 10’
else
Display “ The number is less than 10’
Display nResult
End
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Pseudocode
Advantages of pseudocode are:It is easier and faster to write as it uses English like statements .It does not need to be rewritten if any changes are made because each step is
independent and may be modified without altering the other steps.It can be converted to a program using any programming language.
Disadvantages of pseudocode are:Pseudocode does not provide a graphical representation of an algorithm.Pseudocode depicting too many nested conditions may be difficult to
understand.
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Vocabulary - Pseudocode Declare (variables, literals, procedures, functions…): khai báo Assign (values to variables): gán Operator
Arithmetic: toán tử toán học Relational: toán tử quan hệ Logical: toán tử logic
Operand: toán hạng Operator precedence: toán tử ưu tiên Comment: chú thích Dry run table: chạy thô
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Pseudocode
Beginnumeric nNum1, nResult // Declare variablesnumeric nCons = 10// Direct assignment, initialize first valueDisplay ‘Enter the first number’Accept nNum1 //Accept statementnResult = (nNum1 * nCons) / 73 If nResult > nCons Display “ the number is greater than 10’else
Display “ The number is less than 10’Display nResult
End==================================Variable: nNum1, nResultConstant: nConsExpression: nResult =(nNum1*nCons)/73//: CommentChar, numeric: tupe of data
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Flowchart
A flowchart is a graphical representation of the steps to be ollowed for solving a problem.
It consists of a set of symbols.
Each symbol represents a specific activity.
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Flowchart Advantages of Flowcharts are:
Flowcharts are a better method of communicating logic.
The flowcharts help in analyzing the problems effectively .
The flowcharts act as a guide during the program development phase.
It is easier to debug errors in logic using a flowchart.
The flowcharts help in maintaining the programs.Disadvantages of Flowcharts are:
A lengthy flowchart may extend over multiple pages, which reduces readability.
As flowcharts symbols cannot be typed, drawing a flowchart using any graphic tool is a time consuming process.
The changes made to a single step may cause redrawing the entire flowchart.
A flowchart representing a complex algorithm may have too many flow lines. This reduces readability, and it is time-consuming to draw and understand the logic Readability.
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Pseudocode
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Keywords in Pseudocode
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Keyword in Pseudocode
begin … end: These keywords are used to start and finish
pseudocode. Begin is the first line and end is the last line of
pseudocode.
accept: This keyword is used to obtain an input from a user.
display: This keyword is used to present a result or an output.
if … else… endif: These keywords are used in decision-
making.
//: Comment
Do … while, for …, repeat … until: Represent loop
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Using Pseudocodes to Represent Sequential Code
The pseudocode for adding two numbers is as follows:
// starting the pseudocode
begin
// input consists of accepting two numbers
accept first_number, second_number
// process of adding the two numbers
compute sum as first_number + second_number
// output for displaying the sum
display ‘The sum of given two numbers is’ sum
// ending the pseudocode
end
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Variables and Constants
The internal memory consists of different locations in which data is stored.
A computer needs to identify the memory locations to be able to retrieve values from or store values in them.
A variable refers to the memory location whose value changes during the program execution.
A constant refers to the memory location whose value does not change during the program execution.
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Variables and Constant You need to declare a variable before using it in a program. The declaration of a variable assigns a name to the variable and specifies the type of data
the variable can store.
Naming conventions: The first letter of the variable name might indicate the data type of the variable: cName
and nAge The variable name should clearly describe the purpose of a variable: nScore The variable name should not contain an embedded space or symbols such as ! @ # $ %
^ & * ( ) { } [ ] . , : ; “ ‘ / and \. You can use an underscore when a space is required in a variable name, for example, nBasic_Salary.
If a variable name consists of multiple words without spaces in between, capitalize the first letter of each word for readability. Some examples are nTotalScore and nSumOfSquares.
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Variables and Constant
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Data TypesNumeric:
Numeric variables can contain only numbers.
These variables can be used in arithmetic operations .
Character:Character variables can contain any combination of letters, numbers, and special characters.
These variables cannot be used for calculation.
Let us look to the code of accepting two numbers and displaying the sum with the data type declarations.
begin
numeric nNum1, nNum2, nSum //declaring variables
accept nNum1
accept nNum2
nSum = nNum1 + nNum2
display nSum
end
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Assign values
The variables can be assigned values in the following two methods:Direct assignment
Accept Statement
In the direct assignment method, values can be assigned to variables using the equal to (=) sign, as shown in the following syntax:
variable_name=value
Examples:numeric nHeight, nAge, nCounter
character cCode
nHeight = 172
nAge = 35
nCounter = 0
cCode = “XYZ”
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Assign values
Values can be assigned to variables using the accept statement, as shown in the following syntax.
accept variable_name
Examples: character cName
numeric nAge
display “Enter your name”
accept cName
display “Enter your age”
accept nAge
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Variables and Constant
Identify the variable and constant data in the following situation.
Each day, the courier service delivers some letters. The number of letters is different each day. Regardless of the number of letters delivered by the courier service, they are paid a carrying charge of $5.
Variable:
Constant:
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Operators Arithmetic: +, -, *, /, % Relational: >, <. >=, <=, =, != Logical: AND, OR, NOT
Bảng chân trị (chân lý)
X Y AND(X,Y) OR (X,Y) NOT(X)
0 0 0 0 1
0 1 0 1 1
1 0 0 1 0
1 1 1 1 0
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Problem 1
Create the pseudocode to accept item name, price, and quantity. You need to calculate value as the product of price and quantity, and display the calculated value and the item name using variables.
Answer: begin accept cItem_name, nPrice, nQuantity,
nSale_value
nSale_value = nPrice * nQuantity
display cItem_name
display nSale_value
end
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Priority - PrecedenceOperator Description Associativity Precedence
Level
( ) Parentheses 1! Logical NOT 2* Multiplication Left to right
3/ Division% Modulo division+ Addition Left to right 4- Subtraction< Less than Left to right 5<= Less than or equal to
>= Greater than or equal to
> Greater than= Equal to Left to right 6!= Not equal toAND Logical AND Left to right 7OR Logical OR Left to right 8
Operator Precedence
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Conditional Execution
Many problems require decisions to be made.
All decisions may or may not state an action to be taken if the condition is false.
The following types of decision-making constructs can be used in an algorithm.
if constructs
switch…case constructs
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Conditional Execution
In simple if construct, if the condition specified is true, the statements contained within the if block are executed.
Pseudocode segment to represent the simple if constructs as follows:
if <condition> begin
<statements to be executed if
condition is true>
end
endif
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Conditional Execution
In the if...else construct, the statements within the if block are executed for condition being true and the statements within the else block are executed for condition being false.
if <condition> begin
<statements to be executed if condition is true> endelse begin <statements to be executed if condition is false> endendif
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If Construct
Problem Statement 1:Accept two numbers and print the larger of the two numbers.
Solution: begin
numeric nNum1, nNum2
accept nNum1
accept nNum2
if nNum1 = nNum2
begin
display “The numbers are equal”
end
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If Construct
else
if nNum1> nNum2
begin
display nNum1
end
else
begin
display nNum2.
end
endif // end of second if statement
endif // end of first if statement
end
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If ConstructProblem Statement 2:
Print the value of nX only if the value of nX is greater than 10 and nX is an even number.
Solution:begin
numeric nX
accept nX
if nX > 10 //first if-statement
begin
if nX % 2 =0 //second if-statement
display nX
endif // end of second if-statement
end
endif //end of first if statement
end
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If Construct
Problem Statement 3:To decide about the discount percentage on a TV, the sales person needs to check the type of TV. If the TV is Black and White [B], the discount will be 5 percent of the selling price. If the type of TV is colored [C], then he has to verify the size of TV screen. For 14 inches screen, discount is 8 percent of the selling price and for 21 inches screen, the discount is 10 percent of the selling price. Write a pseudocode to show the discount percentage.
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If ConstructSolution:
begin
numeric nScreen, nDiscount, SP
character cType
accept nType
accept nScreen
accept SP
if cType = ‘B’ // first if statement
begin
compute nDiscount as 5% of SP
end
else
if cType = ‘C’ // second if statement
begin
if nScreen =14 // third if statement
begin
compute nDiscount as 8% of SP end
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If Construct
else
begin
if nScreen = 21 // fourth if statement
begin
compute nDiscount as 10% of SP
end
endif // end of fourth if statement
end
endif // end of third if statement
end
endif // end of second if statement
endif // end of first if statement
end
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The switch…case construct
The switch…case construct enables you to make a decision by selecting from number of choices. The pseudocode of the switch…case construct is as follows:
switch (expression)
begin
case constant 1:
execute these statements
break
case constant 2:
execute these statements
break
default:
execute these statements
end
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Problem 1
Consider the following problem statement for switch…case construct.Amy is writing the algorithm for automated telephone call transfer to various departments of the company such as Marketing, Finance, Customer Care, Human Resource (HR), and Information. Write the solution using Pseudocode.
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Problem 1
begin
numeric nCall
display “If you want to get connected to Marketing
department, press 1, Finance
department press 2, Customer Care
department press 3, HR department press 4.
If you are not sure press any number other
than 1 to 4, the call will be transferred to Information
department”
accept nCall
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Problem 1 switch (nCall)begin
case 1: //case 1 begins Transfer call to the Marketing department breakcase 2: //case 2 begins Transfer call to the Finance department breakcase 3: //case 3 begins Transfer call to the Customer Care department
break case 4: //case 4 begins Transfer call to the HR department break default: //if none of the cases match, the //following line is executed Transfer call to the Information department endend
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Vocabulary - Programming
Decision-making construct: cấu trúc ra quyết định Loop construct: cấu trúc lặp Procedure: thủ tục Function: hàm to invoke: triệu gọi Parameter: tham số scope (local, global): phạm vi biến modular approach of programming: lập trình tiếp cận theo
hướng chia module
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Problem Statement 1:
Problem Statement 1:
Write a pseudocode to display the sum of two numbers by using variables.
Solution: begin
accept nNum1 //assigning values to variables
accept nNum2
nSum = nNum1 + nNum2
display nSum
end
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Problem Statement 2
Problem Statement 2: Write a pseudocode where interest is calculated and displayed for the given balance and rate.
Solution: begin //start
accept Name, Balance, Rate //input
compute Interest as Balance x Rate //process
display Name and Interest //output
end //end
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Problem Statement 3
Problem Statement 3: Write a pseudocode where a number is incremented by 1
Solution: begin //starting
accept Number //input
compute Number as Number + 1 //process
display Number //output
end //end
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Problem 4:
Bình 1 Bình 2Bình rỗng
Numeric nNum1, nNum2, nSwapnNum1 = 5nNum2 = 6nSwap = 0nSwap = nNum1nNum1 = nNum2nNum2 = nSwap
Given: nNum1 = 5, nNum2 = 6Swap their value together.
Bình 1 Bình 2Bình rỗng
Bình 1 Bình 2Bình rỗng
Bình 1 Bình 2Bình rỗng
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A Problem 5:
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Flowchart
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Problem-solving using Flowcharts
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Problem-solving using Flowcharts
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Drawing Flowchart
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Rules of Flowcharting The entire logic of a flowchart should be represented using the standard symbols. „ The flowchart should be clear, precise, and easy to follow. „ Flowcharts can have only one start point and one end point. The steps in a flowchart should follow top-to-bottom or left-to-right approach. All necessary inputs should be listed out in logical order. The start and stop symbols should have only a single flow line. The input, process, output, and display symbols should have two flow lines connecting to the previous symbol and to the next symbol. The decision symbol should have one flow line connecting to the previous symbol but two flow lines connecting to the next symbol for each possible solution such as Yes/No, Y/N, True/False. If too many flow lines make the flowchart complex, it is better to use connector symbols to reduce the number of flow lines. Flowcharts should use page connectors if they extend over multiple pages. It is useful to test the logic of flowchart by passing through it with sample test data.
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Conditional Execution using Flowchart
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Conditional Execution using Flowchart
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Conditional Execution using Flowchart
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Nested If- Statements in Flowchart
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Nested If- Statements in Flowchart
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Switch - case
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Interation
One of the most important characteristics of a computer is its ability to execute a series of instructions repeatedly. This ability of the computer gives you the flexibility to control the number of times a task is to be repeated.
The following types of loops can be used in a pseudocode: � while loop repeat…until loop � for loop � goto �
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For loop
The for loop: The for loop is used when the number of iterations of the loop is known before the control enters the loop.
The for loop consists of the following three parts separated by semicolons.
Initialization expression: The numeric variable is initialized using a value.
Evaluation expression: The condition is tested at the beginning of iteration of the loop. When the expression evaluates to false, the loop terminates.
Increment/decrement expression: The value of the variable is increased.
In a for loop, initializing a variable, evaluating a condition, and incrementing the value of the variable are all specified in one statement.
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For loop
begin
initialize the index
for test the index
begin
increment the index
//perform the statements if the test is true
end
endfor //end of for loop
//perform the statements if the test is false
end
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For Loop
The pseudocode representation of a for loop is as follows:
begin
initialize the index
for test the index
begin
increment the index
// perform the statements if the test is true
end
endfor //end of for loop
// perform the if the test is false
end
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Problem Statement 1
Problem Statement 1:Draw a flowchart to calculate the sum of 10 numbers entered by the user.
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The while Loop
:
:
while (condition)
begin
:
:
end
:
:
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Problem 2begin
numeric nMarks, nTotal, nCounter, nAvg
nMarks = 0
nTotal = 0
nCounter = 0
nAvg = 0
while (nCounter < 30) //while the condition is true
begin
display “Enter the total marks of a student”
accept nMarks
nTotal = nTotal + nMarks
nCounter = nCounter + 1 //increments the counter by one
end
nAvg = nTotal / nCounter //calculates the average
display “The average marks of the class is”
display nAvg //displays the average
end
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The repeat…until Loop
:
:
repeat
begin
:
:
end until (condition)
:
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The goto Statement A goto statement is used in situations in which the execution of a
pseudocode does not follow the steps in a sequential order. To use a goto statement in a pseudocode, you need to use labels. A label
identifies the position in a pseudocode where the control of execution can reach using a goto statement. While assigning name to a label, a colon should follow the label name.
begin
numeric nCounter
nCounter=2
Label1:
nCounter=nCounter+2
display nCounter //displays all the even numbers
if(nCounter<=100)
goto Label1 //transfers the control to Label1
end
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Modular Approach to Programming
A program needs to be amended periodically to respond to changing conditions or requirements.
This encouraged programmers to adopt a more disciplined approach to program writing.
The techniques that were adopted are known as structured programming techniques.
Structured programming includes features that are designed not only to solve the problem at hand but also to make the logic clear to someone reading the program.
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Modular Approach to Programming
Long, continuous programs can be broken up into a series of individual modules that are related to each other in a specified manner.
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Procedure
Procedure:In a modular approach, one of the methods of representing a module is procedure.
The working of a procedure is termed as a call-return mechanism .
The following steps are part of a call–return mechanism:
A procedure is called.
The set of operations stored within the procedure are executed.
The control is returned to the calling code.
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ProcedureDeclaring, Defining, and Invoking Procedures:
Procedures need to be declared and defined before they can be called. The declaration of procedures is similar to a declaration of any other variable in an pseudocode.
Procedures are declared using the following syntax:procedure <procedure_name>
The procedure is defined when the procedure is expressed with its body. The syntax of the procedure definition is:procedure <procedure_name>
begin //the set of statements of a procedure
end
The calling of a procedure is also called invoking a procedure. The method for invoking procedure is known as a procedure call. The syntax of a procedure call is:call <procedure_name>
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Procedure
Problem Statement 1: Accept the test scores for ten students and display their individual averages. The scores of the students cannot be negative.
The following table lists the variables used in the solution.
Variable Data Type Variable Name
Student Name character cStudentName
Score of Test1 numeric nTest1
Score of Test2 numeric nTest2
Score of Test3 numeric nTest3
Average of Test Scores numeric nAverage
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Procedure
Solution:
//code segment to calculate average marks of 10 students
procedure Accept // declaring subprogram Acceptprocedure Average // declaring subprogram Averagebegin numeric nTest1, nTest2, nTest3, nAverage character cStudentName call Accept // calling subprogram Accept call Average // calling subprogram Avearge display cStudentName nAverageend
// code for the subprograms comes here
:
:
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Procedure
Display cStudentName, nAverage
Accept cStudentName
Average
Average
nAverage=(nTest1+nTest2 +nTest3) / 3
Return
Accept
Accept
Accept nTest1
Accept nTest2
Accept nTest3
Display “Test score cannot be less than zero”
IsnTest1>=0 ANDnTest2>=0 AND
nTest3>=0 ?
No
Yes
Return
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Procedure
Problem Statement 2:The total expenditure on salaries for the month needs to be calculated. As per company policy an employee receives a minimum of $500. Depict the logic for automating the task by using pseudocode and flowchart.
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SolutionSolution::
if cChoice = “ Y”
begin
call Accept //invoking Accept
call Summation //invoking Summation
end
:
:
procedure Accept //statements of the subprogram
:
begin
accept nSalary
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Solution
if nSalary >=500
begin
return // returning the value
end
else
begin
display ‘Salary cannot be less than $500”
end
endif
end // end of the subprogram
procedure Summation // statements of the subprogram
begin
nTotSalary = nTotSalary +nSalary
return nTotSalary
end
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Procedure Parameters
Procedure Parameters:
Parameters are like a bridge between the procedure and the calling code.
Parameters comprise data that is used and processed by a procedure.
Parameters can be variables of the numeric or character data type.
Parameters are used to perform the following tasks:Send data to a procedure
Retrieve data from a procedure
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Function
Function:A function is a block of statements that perform a specific task. The underlying fundamental of functions and procedures are very similar, and they can be used interchangeably.
The difference between a function and a procedure is that a procedure does not return any value to a calling program while a function returns a value to the calling program after it is executed.
The functions in a pseudocode interact with each other by passing and receiving data. Functions also operate on the call–return mechanism. The following are the steps in the call–return mechanism using functions:
The function is called from the calling code.
The sets of operations within the functions are executed.
The execution is returned to the calling code using a return value
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Function
Declaring, Defining, and Invoking Functions:
Functions are declared like any other procedure or variable. The declaration format is function <function_name>
The function are defined same as procedures. The only difference is that they have a return statement at the end. The syntax of the function definition is:function <function_name>
begin
//the function statements
return // The function returns some value
end
After a function is declared, it can be invoked from the pseudocode. The method for invoking functions is known as a function call. The syntax for the function call is:
call <function_name>
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Function Parameters
Function Parameters:Function parameters form an interface between the function and the calling code.
Functions accept values in the form of parameters. If parameters are specified, they should be separated using commas.
Unlike procedures, the functions use the parameters only for receiving data from the calling code.
They send value to the calling code using the return statement. Therefore, functions have only input parameters.
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Scope of Variables
Scope of Variables:
Variables can be declared within or outside the begin…end block of a main pseudocode, procedure, or function.
Depending on the place where variables are declared the variables have two types of scope.
Local Scope
Global Scope
The variables that are declared inside the begin...end block of a main pseudocode, function, or procedure have local scope and they are called local variables.
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Scope of Variables
The following pseudocode describes the local scope of the variables.
begin
numeric nNum
display “Enter any number”
accept nNum
if (nNum > 10)
begin
numeric nRemainder
nRemainder = nNum % 2
display nRemainder
end
endif
end
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Scope of Variables
Following pseudocode describes the local scope using function.begin numeric nNum display “Enter any number” accept nNum if (nNum > 10) begin call displayRemainder(nNum) display nRemainder //an invalid statement end
endif end function displayRemainder (numeric nNumber) begin numeric nRemainder nRemainder = nNumber % 2 display nRemainderend
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Scope of Variables
Procedure Test()begin numeric nX, nY nX = 6
nY = 10 Display nX, nY Call Test ()
EndProcedure Test()Begin
numeric nXnx = 9Display nX, nY
End
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Scope of Parameters
Scope of Parameters:
The parameters of a procedure or function are variables that can be accessed only from inside the procedure or the function.
This implies that the parameters act as the local variables of a function or a procedure.
The following comprise the scope of parameters: Parameters exist only inside the function or procedure for which they are defined. They cannot be accessed from outside the function or procedure.
They retain their value until the function or procedure is executed.
Parameters are initialized every time the function or procedure is called.
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Questions
A compiler is: A high-level language Language-specific A machine language A source code
The symbol that represents comments in a flowchart is:A procedure/subroutine symbolAn input symbolAn annotation symbolA flow line
A detailed flowchart is called a: Macro flowchart Lengthy flowchart Micro flowchart Detailed flowchart
Which of the following is NOT a type of algorithm?
Flowchart Program Pseudocode Decision table
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Question
Literals are: Values that change continuously Memory locations Values that do not change Names given to variables
A statement consisting of variables, literals, constants, and operators is called a/an:FunctionIdentifierOperatorExpression
Input is accepted using the keyword accept in:PseudocodeA FlowchartAn AlgorithmAn Expressiont
Which operators are used to test the relationship between two variables or between a variable and a constant?Arithmetic operatorsLogical operatorsRelational operatorsSpecial operators
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