Quick fun with Copilot, calculate pi!

calculate_pi.c

#include <stdio.h>
#include <math.h>

// a function to calculate the value of pi
double calculate_pi(int n) {
    double pi = 0.0;
    int i;
    for (i = 0; i < n; i++) {
        pi += pow(-1, i) / (2 * i + 1);
    }
    return 4 * pi;
}

int main() {
    int n;
    printf("Enter the number of terms: ");
    scanf("%d", &n);
    printf("The value of pi is %f\n", calculate_pi(n));
    return 0;
}

pi.c

#include <math.h>
#include <stdio.h>

int main(void)
{
    double pi = 0.0;
    double denom = 1.0;
    double sign = 1.0;
    int i;

    for (i = 0; i < 1000000; i++) {
        pi += sign / denom;
        denom += 2.0;
        sign = -sign;
    }
    pi *= 4.0;
    printf("pi = %f\n", pi);
    return 0;
}