C/Data Type/Register
Register variable: faster
<source lang="cpp">
- 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;
}
</source>
Use register int in function
<source lang="cpp">
- include <stdio.h>
main() {
register int i = 0; for( i = 0; i < 2; i++) { printf("i = %d\n",i); }
}
</source>