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Register Storage Class in C

"register" storage class in C​

  • The register storage class in C is used to declare local variables that are stored in the CPU register instead of memory, and that can result in faster access times.

Syntax:

register data_type variable_name;

  • When a variable is stored in a register, the processor can access its value faster than when it is stored in memory.

  • This can be particularly beneficial for frequently used variables or loop counters, as it can result in improved performance of the program.

Example 1​

#include <stdio.h>

int main()
{
    register int i;
    for (i = 0; i < 10; ++i)
    {
        printf("%d ", i);
    }
    return 0;
}
Output:
note

Using register storage class does not guarantee that a variable will be stored in a register, as it depends on the implementation and available registers.