Study of Register Storage Class.

#include <stdio.h>
#include <time.h>

int main(void)
{
auto long int x, y;
//register long int x, y;
time_t first, second;

first = time(NULL);

for(x = 1 ; x <= 50000L ; x++)
for(y = 1 ; y <= 50000L ; y++);

second = time(NULL);

printf( "\nThe difference is: %f seconds\n", difftime(second,first));

return 0;
}