zoj 1337 Pi

#include "iostream"#include "memory.h"#include "math.h"#include "stdio.h"using namespace std;int input[60];int main(){    memset(input, 0, sizeof(input));    int num, i, j, count, sumcount, g, x, y;    double pi, ans;    while (cin >> num && num)    {          count = ans = pi = g = 0;          sumcount = num * (num - 1) / 2;          for (i = 1; i <= num; i++)               cin >> input[i];           for (i = 1; i < num; i++)          for (j = i + 1; j <= num; j++)          {  x = input[i], y = input[j];              while (y && x)              {                    y = y % x;                    if (y)                    x = x % y;              }              g = (y != 0) ? y : x;              if (g == 1)              count++;          }          if (count == 0)          cout << "No estimate for this data set." << endl;          else          {              ans = 6.0 * sumcount / count;//一直都WA，原来问题出现在这里，应该是6.0，而不是6，所以精度降低了！粗心！              //pi = pow(ans , 1.0/2);  pi = sqrt(ans);              printf("%.6lf\n", pi);          }    } }