Register variable: faster : Register « Data Type « C / ANSI-C

1. C / ANSI-C
2. Data Type
3. Register

Register variable: faster

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

int i;  /* This will not be transformed into a
           register variable because it is global.*/

int main(void)
{
  register int j;

  int k;
  clock_t start, finish;

  start = clock();
  for(k = 0; k < 1000; k++)
    for(i=0; i<32000; i++) 
        ;
        
  finish = clock();
  printf("Non-register loop: %ld ticks\n", finish - start);

  start = clock();
  for(k = 0; k < 1000; k++)
    for(j = 0; j < 32000; j++)
        ;
  finish = clock();
  printf("Register loop: %ld ticks\n", finish - start);

  return 0;
}


           
       

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