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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. int main() {
  5.     srand(time(0));
  6.  
  7.     int nVals[] = {1000, 10000, 100000};
  8.     for (int i = 0; i < 3; i++) {
  9.         int n = nVals[i], cnt = 0;
  10.         for (int j = 0; j < n; j++) {
  11.             double x = (double)rand() / RAND_MAX;
  12.             double y = (double)rand() / RAND_MAX;
  13.             if (x*x + y*y <= 1.0) cnt++;
  14.         }
  15.         double pi = 4.0 * cnt / n;
  16.         cout << "N=" << n << " -> pi≈" << pi << endl;
  17.     }
  18.     return 0;
  19. }
  20.  
  21. /*
  22. Q1. How does the estimate change with larger N?
  23. = Increasing N improves the estimate and makes it closer to π.
  24.  
  25. Q2. How close does it get to actual π?
  26. = For N=1000, error is ~±0.1; N=10000, error ~±0.03; N=100000, error ~±0.01. 
  27. Higher N gives values nearer to 3.14159.
  28. */
  29.  
Success #stdin #stdout 0.01s 5320KB
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N=1000 -> pi≈3.18
N=10000 -> pi≈3.1404
N=100000 -> pi≈3.14252
https://ideone.com/eb414D
language:
C++ (gcc 8.3)
created:
6 days ago
visibility:
public

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