Leibniz formula for π (pi)

#include <cmath>
 
int main() {  
    float a = 1.0;  
    float b = a - (1.0 / 3.0);  
    int znak = 1;  
    unsigned i = 3;  
  
    while (fabs(b - a) > 0.001) {  
        a = b;  
        b += znak * (1.0 / (2.0 * i - 1.0));  
        znak *= -1;  
        i++;  
    }  
}

int main() {  
    float sum = 1;  
    int sign = -1;  
    unsigned n = 10000;  
  
    for (int i = 2; i <= n; i++) {  
        sum += sign * (1.0 / (2.0 * i - 1.0));  
        sign *= -1;  
    }  
  
    std::cout << sum * 4;  
}