C language provides three data types to handle whole numbers
int Data Type
The data type int is used to store whole numbers (integers). The integer type
space of 4 bytes (32 bits for windows operating system) in memory. And it is mentioned as ‘int’ which is a reserved word of C, so we cannot use it as a variable name.
In programming before using any variable name we have to declare that variable with its data type. If we are using an integer variable named as ‘i’, we have to declare it as int i ;
The above line is known as declaration statement. When we declare a variable anyway, it reserves some space in memory depending on the size of data type and labels it with the variable name. The declaration statement int i ; reserves 4 bytes of memory and labels it as ‘i’. This happens at the execution time.