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C Language: Integer Variables

This C tutorial explains how to declare and use integer variables with syntax and examples.

Description

There are the following integer types available in the C Language:

  • short int
  • unsigned short int
  • int
  • unsigned int
  • long int
  • unsigned long int

For the purposes of this tutorial, we will focus on the basic int type.

Syntax

The syntax for declaring integer variables is:

int variable_name1 [= value1];

Or the syntax for declaring multiple integer variables is:

int variable_name1 [= value1] [, variable_name2 [= value2], ... variable_name_n [= value_n]];

Parameters or Arguments

variable_name1
The name of the first variable to declare.
value1
Optional. If provided, it is the value to assign to variable_name1.
variable_name2, ... variable_name_n
Optional. These are additional variables that will be declared with the same C type.
value2, ... value_n
Optional. These are the values that you wish to assign to variable_name2 through variable_name_n.

To declare an integer variable with a type other than int, simply replace the int keyword in the syntax above with your selected type.

For example:

short int variable_name1 [= value1];

Example - Declaring a variable

Let's look at an example of how to declare an integer variable in the C language.

For example:

int age;

In this example, the variable named age would be defined as an int.

Below is an example C program where we declare this variable:

#include <stdio.h>

int main()
{
   int age;

   age = 10;
   printf("TechOnTheNet.com is over %d years old.\n", age);

   return 0;
}

This C program would print "TechOnTheNet.com is over 10 years old."

Example - Declaring a variable and assigning a value

You can define a variable as an integer and assign a value to it in a single declaration.

For example:

int age = 10;

In this example, the variable named age would be defined as an integer and assigned the value of 10.

Below is an example C program where we declare this variable and assign the value:

#include <stdio.h>

int main()
{
   int age = 10;

   printf("TechOnTheNet.com is over %d years old.\n", age);

   return 0;
}

This C program would print "TechOnTheNet.com is over 10 years old."

Example - Declaring multiple variables in a statement

If your variables are the same type, you can define multiple variables in one declaration statement.

For example:

int age, reach;

In this example, two variables called age and reach would be defined as integers.

Below is an example C program where we declare these two variables:

#include <stdio.h>

int main()
{
   int age, reach;

   age = 10;
   reach = 100;
   printf("TechOnTheNet.com is over %d years old and reaches over %d countries.\n", age, reach);

   return 0;
}

This C program would print "TechOnTheNet.com is over 10 years old and reaches over 100 countries."

Example - Declaring multiple variables in a statement and assigning values

If your variables are the same type, you can define multiple variables in one declaration statement. You can also assign the variables a value in the declaration statement.

For example:

int age = 10, reach = 100;

In this example, two variables called age and reach would be defined as integers and be assigned the values 10 and 100, respectively.

Below is an example C program where we declare these two variables and assign their values:

#include <stdio.h>

int main()
{
   int age = 10, reach = 100;

   printf("TechOnTheNet.com is over %d years old and reaches over %d countries.\n", age, reach);

   return 0;
}

This C program would print "TechOnTheNet.com is over 10 years old and reaches over 100 countries."

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