Data types in C


C lang is easy to understand. Only what matters is the way you see it.The majority of meaningful programs written in C manipulate variables and constants. A variable is a symbolic name for an object that changes  or  varies during a program execution. In C, all variables must be declared before they can be used. In other words, you should tell the compiler to associate a type with each variable or constant before its first use. let see the following program.

#include <stdio.h>
int main (void)
{
        int m, d, c;
        int const letter = '69';
        float x = 10;
        float y = 3;
}

 variables- m, d, c, x, y, and the constant -letter. We also initialized the values of variables x and z to 10 and 3 respectively, and the value of letter to 69. Declaration statement for a variable looks like

type_variable type_name;

 To declare a constant you should add the word const after or before the type of the constant. The following declarations are identical.

variable_type const variable_name;
const variable_type variable_name;

The most fundamental data types   in C are:

  • integral types

  • floating types

  • arithmetic types

The integral types are designed for working with the integer values. There are nine integral types and their variations in C. They are designated by these keywords:

  • char, signed char, unsigned char

  • short, int, long

  • unsigned short, unsigned int, unsigned long

 

The data type int is the principle working type of the C language. For example

int num_of_students = 50;

Now you can perform arithmetic (and some other) operations on this number. Let's assume that two students dropped the class. The following example will calculate and display the number 48, which is the number of students left in the class (50 - 2).

int main (void)
{
        int num_of_students = 50;
        int students_left = 2;
        num_of_students = num_of_students - students_left;
        printf ("%d, num_of_students);
}

 In the above example, the data type short can be used instead of int if memory storage is of concern. You'll be able to keep track of less number of students than with the int type but enough for the whole group to count. In a similar fashion, the type long might be used in situations where larger integer values are needed.

The char type is used to represent characters. int and char variables are used for the same purpose because characters are stored in the computer as numbers. To illustrate this idea let's take a look at the following code:

int i = 'a';
int k = 97;
printf ("%c", i);          /* a is printed */
printf ("%c", k );        /* a is printed */

Here the same letter "a" will be printed twice because the integer value 97 corresponds to the letter "a". Usage of %c with printf() tells the computer to display a character.

Finally, there are three floating types in C:

  • float

  • double

  • long double