简单算法之概率计算PI

#include "iostream"
#include "cstdlib"
#include "ctime"

#define N  50000

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

srand(time(NULL));//初始化一个随机数

for(i = 1;i<N;i++)
{
x=(double)rand()/RAND_MAX;
y=(double)rand()/RAND_MAX;
if((x*x+y*y)<1)
sum++;
}

std::cout<<"PI =  "<<(double)4*sum/N<<std::endl;//怎么控制cout输出的字节长度
return 0;
}