Post on 05-Apr-2018
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C++ Data Types
Built-In Type
Integral type - int, char
Floating typefloat, double
Void
Used to specify the return type of a function
when it is not returning any value
To indicate an empty argument list to a
function. Example : void fun (void);
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C++ Data Types
Used in declaration of generic pointers. Void *gp;
A generic pointer can be assigned a pointer
value of any basic data type, but it may not
be dereferenced.
For ex: int * ip; gp = ip; // assigns int
pointer to void pointer.
But, *ip = *gp; is illegal;It would not make sense to dereference a pointer
to a void value.
LOOPS
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C++ Data Types
User-defined type
1. Structure
2. Union3. Class
4. Enumeration
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C++ Data Types
Structure and Union in C.
They are used in C++ with some added
features of object oriented languages.
Class is used in c++.
The class variables are known as objects.
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Enumerated Data type
It is user defined data type which provides a
way for attaching names to numbers.
It increases the comprehensibility of the
code.
The enum keyword automatically
enumerates a list of words by assigning themvalues 0,1,2 and so on.
It is used to create symbolic constants.
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Enumerated Data type
The enum statement is similar to the structstatement.
Ex : enum shape {circle, square, triangle}
enum color{ red, blue, green, yellow}
They differ from enum in C .
In C++, they can be used as new type names.
By using, tag names we can declare new
variables.
shape ellipse; // ellipse is of type shape.
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Enumerated Data type
ANSI C defines the types of enums to be ints. In c++, each enumerated data type retain its
own separate type.
C++ does not permit an int value to beautomatically converted to an enum value.
Ex : color background = blue; // allowed
color background = 7; // error in c++ color background = (color) 7; // ok
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Enumerated Data type
An enumerated value can be used in placeof an int value.
Ex : int c = red; // valid, color type
promoted to int By default, enumerators are assigned
integer values starting from 0. We can
override these values by :enum color {red= 8, blue = 4, green};
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Enumerated Data type
C++ also permits the creation of anonymous
enums ( enums with out tag names)
Ex : enum {off, on};
int switch_1 = off;
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Derived data types
Array : contiguous/ continuous memory space.
Character arrays are initialized in different
way:
Ex in C :char string[3] = xyz // programmer
intends to leave out the null character \0.
Ex in C++ : char string[4] = XYZ
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Derived data types
Function: A block of code that is to beexecuted to serve some purpose.
Pointers:
int * ip; // int pointer
ip = &x; // address of x assigned to p;
*ip = 10; // 10 assigned to x through
indirection.
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Difference Between The Two?
Constant pointer
Pointer to a constant
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Constants
Constants refer to fixed values that do notchange during the execution of a program.
They include integers, characters, floating
point numbers and strings.Literal constant do not have memory locations.
Examples:
123 // decimal integer
12.34 // floating point integer
037 // Octal integer
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Constants
0x2 //hexadecimal integer C++ //string constant
A // character constant
Lab // wide-character constant wchar-_t type is a wide-character literal
introduced by ANSI C++ and is used for character
sets that cannot fit a character into a single byte.
Wide-character literals begin with the letter L.
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Symbolic constants
They can be created as follows:
1. Using the qualifier const, and
2. Defining a set of integer constants using enum
keyword.
Any value declared as const cannot be modifiedby the program in any way.
ex : Const int size = 10;
C++ requires a constant to be initialized. ANSI C does not require an initialization, it will
give a default value 0.
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Symbolic constants
Enumeration example :enum { x, y, z};
const x = 0;
const y = 1;
const z =2;
Or explicitly, enum {x=100, y = 50,z=200};
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Control Structures
Three control structures: Sequence structure ( straight line)
Selection structure (branching)
Loop structure ( iteration or repetition)
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Selection structure (branching)
Simple If statement
if (condition){ // code
}
Ifelse statementIf (condition)
{
// code}
Else
{// code}
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Switch statement
This is multiple branching statement, basedon a condition.
The control is transferred to one of themany possible points.
Syntax:
switch (expression)
{
case 1:
{ //code
}
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Switch statement
case 2:{ //code
}
Default:
{// code
}
}
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LOOPS
Do While :exit controlled loopDo
{
// code
}while (condition is true);
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LOOPS
While Loop : entry controlled loop
while (condition is true)
{ // code
} For Loop : entry controlled and action will
repeated a predetermined no. of times
for( initial value; test; increment)
{ // code
}