Implementation of Trapezoidal Rule (Integral Approximation) written in C++.
Enter begining of interval: -2 Enter end of interval: 2 Enter number of iterations: 1000000 Integral is equal to: 5.33335
#include <iostream> // ? 2018 TheFlyingKeyboard and released under MIT License // theflyingkeyboard.net using namespace std; double function(double x); int main() { double intervalBegin; double intervalEnd; int count; double integral; double step; cout << "Enter begining of interval: "; cin >> intervalBegin; cout << "Enter end of interval: "; cin >> intervalEnd; cout << "Enter number of iterations: "; cin >> count; step = (intervalEnd - intervalBegin) / count; integral = 0.5 * (function(intervalBegin) + function(intervalEnd)); for (int i = 0; i < count; ++i) { integral += function(intervalBegin + step * i); } integral *= step; cout << "Integral is equal to: " << integral << endl; int a; cin >> a; return 0; } double function(double x) { return x * x; }
C++ Trapezoidal Rule