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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <math.h>
  4.  
  5. #define M_PI 3.14159265
  6.  
  7. int main() {
  8.     double a, b, s, x[4], y[4], r, true_value;
  9.     int count, m, n;
  10.  
  11.     x[0] = 1.0; y[0] = 0.0;
  12.     x[1] = 0.0; y[1] = 1.0;
  13.     x[2] = -1.0; y[2] = 0.0;
  14.     x[3] = 0.0; y[3] = -1.0;
  15.  
  16.     r = 1.0;  
  17.     true_value = (M_PI - pow(3, 1.5) + 3) / 3.0;  
  18.  
  19.     for (n = 10; n < 100000; n *= 5) {
  20.         count = 0;
  21.         s = 0.0;
  22.  
  23.         for (m = 0; m < n; m++) {
  24.             a = (double)rand() / RAND_MAX * 2.0 - 1.0;  
  25.             b = (double)rand() / RAND_MAX * 2.0 - 1.0;  
  26.  
  27.             int in_all_circles = 1;
  28.             for (int i = 0; i < 4; i++) {
  29.                 double dist = (a - x[i]) * (a - x[i]) + (b - y[i]) * (b - y[i]);
  30.                 if (dist >= r) {
  31.                     in_all_circles = 0;
  32.                     break;
  33.                 }
  34.             }
  35.  
  36.             if (in_all_circles) {
  37.                 s += 1.0;
  38.             }
  39.             count++;
  40.         }
  41.  
  42.         s /= count;  
  43.         s *= 4.0;    
  44.  
  45.         printf("%d\t%f\n", n, fabs(s - true_value));
  46.     }
  47.  
  48.     return 0;
  49. }
Success #stdin #stdout 0s 5284KB
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stdin
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Standard input is empty
stdout
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10	0.315147
50	0.315147
250	0.315147
1250	0.315147
6250	0.315147
31250	0.315147
https://ideone.com/CaFwZk
language:
C (gcc 8.3)
created:
4 days ago
visibility:
public

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