c 计算时间

#include "time.h"

#include "sys/time.h"


long long time1;

long long time2;

double usetime;

struct timeval tim;


/**********开始时间********************/

gettimeofday(&tim,NULL);

printf("start: %lld \n",tim.tv_sec*1000 + tim.tv_usec/1000);

time1 =tim.tv_sec*1000 + tim.tv_usec/1000;


/**********结束时间********************/

gettimeofday(&tim,NULL);

printf("end: %lld \n",tim.tv_sec*1000 + tim.tv_usec/1000);

time2 =tim.tv_sec*1000 + tim.tv_usec/1000;


/**********计算********************/

usetime = time2-time1;

printf("加密所用时间 %.3f s\n",usetime/1000);