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