Integers is the set of numbers that include all the whole numbers and their negative values.

The set of integers can be represented as -∞ .... -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5.....∞

In programming, integer is a data type used to represent integer values. We can declare a variable as an integer type or define the result of a function or expression as of integer type. 

A variable declared as an integer type occupies a specified amount of memory space in computer. The amount of space occupied depends on the computer system you are using - typicall ranging from 4 bytes to over 64 bytes. 

A variable defined as an integer type cannot store any other types of data such as character like a,b,c or floating-point numbers like 5.43, -0.43.

In C++, an integer variable is declared as

int a = 5;

In JavaScript, the type is inferred by the interpreter so we just write

var a = 5;
C Program to Add Two Integers