请问如何用C语言做蒙特卡罗方法sin函数的积分? 0~Pi/2 请给我完整的过程

#include "stdio.h"
#include "time.h"
#include "math.h"
#include "dos.h"

#define PI 3.1415926

main()
{ double x,y,sum=0;
int i;

for(i=0;i<=100;i++)
{ srand(time(0));
x=rand()%10000;
x=x/10000*PI/2;
sleep(1);
srand(time(0));
y=rand()%10000;
y=y/10000;
if(y<=sin(x)) sum++;
clrscr();
printf("%d%",i);
}
clrscr();
printf("%f ",sum/--i);
}
TC上没问题 VC上有点问题~~~~