A Beginner's Guide to Popping the Bonnet and Getting Your Hands Dirty
Week 1: Getting Dirty - Part 1
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Transcript of Week 1: Getting Dirty - Part 1
Agenda
• Expressions, Types, and Variables• Control Statements - Selection• Control Statements - Loops• Methods• Namespaces• Introduction to Classes• Class Inheritance• Polymorphism
Expressions, Types, and Variables
• Variables: storage locations for data• int num = 428;
• C# is a strongly typed language. • All operations are based on variable Types
• C# simple types consist of:• Boolean Type• 3 numeric type: Integrals, Floating Point, Decimal• String
Expressions, Types, and Variables
• The Boolean Type• Declared by keyword: bool• Has two values: true or false
Expressions, Types, and Variables
• In C++, a value of type bool can be converted to a value of type int; in other words• false is equivalent to zero and true is equivalent to nonzero values.
• In C#, there is no conversion between the bool type and other types.
Expressions, Types, and Variables
• Integral Types• Number, either signed and unsigned and char type
Expressions, Types, and Variables
• The String Type• A string is a sequence of text characters.• “This is a string example”• Some characters are not printable
Expressions, Types, and Variables
• Operands and Operators• Operand is a piece of information or data• Operator specifies what action should be done with the operand(s).• operandOne operator operandTwos
• Expressions• An expression is simply one or more operands and their associated operator
treated as a single entity.• answer = operand1 / operand2
Expressions, Types, and Variables
• Statements• In C#, a program statement is one or more expressions terminated by a
semicolon. • answer = operand 1 / operand2;
Expressions, Types, and Variables
• solution = 2 + 3 * 4 + 5;• Overriding the default Precedence order• Solution = (2 + 3) * (4 + 5);
Control Statements - Selection
• If statements• An if statement allows you to take different paths of logic, depending on a
given condition.• There are two forms of OR:
• Regular OR (|) operator will evaluate both sub-expressions every time. • Conditional OR (||) will evaluate the second sub-expression only if the first sub-
expression evaluates to false.• There are two forms of AND:
• Regular AND operator will evaluate both expressions every time. • Conditional AND operator will evaluate the second sub-expression only when the first
sub-expression evaluates to true.
Control Statements - Selection
• Switch Statements• A type of selection control mechanism used to allow the value of a variable or
expression to change the control flow of program execution via a multiway branch.
• Break!• Go to!
Control Statements - Loops
• Learn the while loop• A while loop will check a condition and then continues to execute a block of
code as long as the condition evaluates to a boolean value of true.
• Learn the do loop• A do loop is similar to the while loop, except that it checks its condition at the
end of the loop.
Control Statements - Loops
• Learn the for loop• By using a for loop, you can run a statement or a block of statements
repeatedly until a specified expression evaluates to false.
• Learn the foreach loop• The foreach statement repeats a group of embedded statements for each
element in an array or an object collection.
Methods
• Methods are to split our logic into units• Name should be meaningful• Should be associated with the task• Parameters are to transfer information to and from method
attributes modifiers return-type method-name(parameters){
statements}
Namespaces
• Namespaces are C# program elements designed to help you organize your programs.• Also to avoid name conflicts
Introduction to Classes
• Classes are templates to objects• Constructors• Instance and Static methods, again!• Destructors
• To release the allocated resources
Inheritance
• Inheritance is one of the primary concepts of object-oriented programming. It allows you to reuse existing code.
Polymorphism
• It allows you to invoke derived class methods through a base class reference during run-time. • Sending the same message, getting the correct response