exp n terms 1 call

01.exp.cpp

// 01.exp.cpp
// juanfc 2024-10-22
// calculate the factorial directly by adding n terms
// of its series development
// Look at https://en.wikipedia.org/wiki/Taylor_series
// https://gist.github.com/juanfal/8c7b827df2417ce271d25a4d06468847

#include <iostream>
using namespace std;

int main()
{
    double exp(double x, int n=10);

    for (double x = 1; x < 100; x+=10)
        cout << "exp(" << x << ")= " << exp(x) << endl;

    return 0;
}

double exp(double x, int n=10)
{
    double fact = 1;
    double pot = 1;
    double s = 0;

    for (int i = 1; i <= n; ++i) {
        s += pot/fact;
        pot *= x;
        fact *= i;
    }
    return s;
}