time_t輸出時間

#include<stdio.h>
#include<time.h>
#include<windows.h>
#include<stdlib.h>
main()
{
    clock_t t1,t2;
    time_t now;
    time(&now);
    printf("It is now %s",ctime(&now));
    t1=clock();                 //起始時間
    for(int i=10;i>=1;i--)
    {
        printf("%2d/n",i);
        Sleep(1000);
    }
    t2=clock();                 //結束時間
    printf("%.2f/n",(t2-t1)/CLK_TCK);     //CLK_TCK=1000
    time(&now);
    printf("It is now %s",ctime(&now));
    printf("The strlen is %d/n",strlen((ctime(&now))));
    system("pause");
}