Data Types and modifiers In C++

Data types in C++

Data Types In C++

In computer programming, a data type or simply type is an attribute of data that tells the compiler or interpreter how the programmer intends to use the data. It tells about the size and behavior of data. While writing any code we may need to store our data in different forms and of different size. To do this we need different variables of different data types. e.g if we want to store numbers we may need different data type than that of we required to store alphabets. 

When we store something, it means we are reserving space from computer memory. Different data types occupies different memory spaces. If we don't know about them then we may fail to built robust program. so lets see what are the data types that C++ supports and what are their keywords.

1. 
   

• Primary(Built-in) Data Types:
• character
• integer
• floating point
• double floating point
• boolean
• wide character
• User Defined Data Types:
• Structure
• Union
• Class
• Enumeration
• Derived Data Types:
• Array
• Function
• Pointer
• Reference

Modifiers: A modifier is used to alter the meaning of the base type so that it more precisely fits the needs of various situations.

Various Modifiers used in C++ are:

1. Signed
2. Unsigned
3. Long
4. Short

Now lets see the keywords associated with the different data types in C++.

Keyword	Data Type
bool	Boolean
char	Character
int	Integer
float	Floating point
double	Double floating point
void	Valueless
wchar_t	Wide character

 The table below shows the different data types with modifiers  along with their size in bytes and range. I have derived these information from different books and internet. However the size and range might vary slightly with the compiler and system you are using.

   

Type	Range	Size in Byte
char	-127 to 127 or 0 to 255	1
unsigned char	0 to 255	1
signed char	-127 to 127	1
int	-2147483648 to 2147483647	4
unsigned int	0 to 4294967295	4
signed int	-2147483648 to 2147483647	4
short int	-32768 to 32767	2
unsigned short int	0 to 65,535	-
signed short int	-32768 to 32767	-
long int	-2,147,483,648 to 2,147,483,647	4
signed long int	same as long int	4
unsigned long int	0 to 4,294,967,295	4
float	+/- 3.4e +/- 38 (~7 digits)	4
double	+/- 1.7e +/- 308 (~15 digits)	8
long double	+/- 1.7e +/- 308 (~15 digits)	8
wchar_t	1 wide character	2 or 4

Size of() operator:

To find the actual size (bytes of memory) occupied by the data type in your system you can use Size of () operator.

 #include <iostream>

using namespace std;

int main() {

cout << "Size of char : " << sizeof(char) << endl;

cout << "Size of int : " << sizeof(int) << endl;

cout << "Size of short int : " << sizeof(short int) << endl;

cout << "Size of long int : " << sizeof(long int) << endl;

cout << "Size of float : " << sizeof(float) << endl;

cout << "Size of double : " << sizeof(double) << endl;

cout << "Size of wchar_t : " << sizeof(wchar_t) << endl;

return 0;

}

 The output of above code is:

Size of char : 1

Size of int : 4

Size of short int : 2

Size of long int : 4

Size of float : 4

Size of double : 8

Size of wchar_t : 4