磁盘IO操作指令和普通表达式指令所消耗的时间对比

# disk io VS statements

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


int main(int argc, char* argv[]){
    int i, to, sum = 0;
    FILE *fp = fopen("file", "w");
    to = atoi(argv[1]);
    clock_t start = clock(), diff;
    for(i=1; i<=to; i++){
        sum += sum + i;
        //printf("%d\n", sum);
        fprintf(fp, "%d", sum);
        // i++;
    }
    diff = clock() - start;
    int msec = diff * 1000 / CLOCKS_PER_SEC;
    printf("Time taken %d seconds %d milliseconds\n", msec/1000, msec%1000);
}