fork download
copy 
  1. #include <iostream>
  2. #include <iomanip>
  3. #include <random>
  4. #include <cmath>
  5.  
  6. using namespace std;
  7.  
  8. /* ===========================
  9.    MONTE CARLO
  10.    =========================== */
  11. long double monteCarlo(unsigned long long n) {
  12.     mt19937_64 gen(123456); // stałe ziarno dla powtarzalności
  13.     uniform_real_distribution<long double> dist(-1.0L, 1.0L);
  14.  
  15.     unsigned long long inside = 0;
  16.  
  17.     for (unsigned long long i = 0; i < n; ++i) {
  18.         long double x = dist(gen);
  19.         long double y = dist(gen);
  20.  
  21.         if (x * x + y * y <= 1.0L)
  22.             inside++;
  23.     }
  24.  
  25.     return 4.0L * inside / n;
  26. }
  27.  
  28. /* ===========================
  29.    METODA PROSTOKĄTÓW
  30.    π = 4 * ∫₀¹ 1/(1+x²) dx
  31.    =========================== */
  32. long double rectangles(unsigned long long n) {
  33.     long double h = 1.0L / n;
  34.     long double sum = 0.0L;
  35.  
  36.     for (unsigned long long i = 0; i < n; ++i) {
  37.         long double x = i * h;
  38.         sum += 1.0L / (1.0L + x * x);
  39.     }
  40.  
  41.     return 4.0L * h * sum;
  42. }
  43.  
  44. /* ===========================
  45.    METODA TRAPEZÓW
  46.    =========================== */
  47. long double trapezoids(unsigned long long n) {
  48.     long double h = 1.0L / n;
  49.     long double sum = 0.5L * (1.0L / (1.0L + 0.0L) +
  50.                               1.0L / (1.0L + 1.0L));
  51.  
  52.     for (unsigned long long i = 1; i < n; ++i) {
  53.         long double x = i * h;
  54.         sum += 1.0L / (1.0L + x * x);
  55.     }
  56.  
  57.     return 4.0L * h * sum;
  58. }
  59.  
  60. /* ===========================
  61.    MAIN
  62.    =========================== */
  63. int main() {
  64.  
  65.     const unsigned long long n = 10000000ULL;  // <<< TUTAJ ustawiasz dokładność
  66.  
  67.     long double pi_mc   = monteCarlo(n);
  68.     long double pi_rect = rectangles(n);
  69.     long double pi_trap = trapezoids(n);
  70.  
  71.     cout << fixed << setprecision(20);
  72.  
  73.     cout << "Monte Carlo:  " << pi_mc   << endl;
  74.     cout << "Prostokaty:   " << pi_rect << endl;
  75.     cout << "Trapezy:      " << pi_trap << endl;
  76.  
  77.     return 0;
  78. }
Success #stdin #stdout 0.49s 5288KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Monte Carlo:  3.14081960000000000007
Prostokaty:   3.14159275358979148888
Trapezy:      3.14159265358979148883
https://ideone.com/MABBIg
language:
C++ (gcc 8.3)
created:
16 hours ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!