PSP0 Homework

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

int main(void) {
    double x, n, s2, sum, mean;

    fscanf(stdin, "%lf", &x);
    sum = mean = x;
    n = 1.0;

    while( fscanf(stdin, "%lf", &x) == 1) {
        sum += x;
        n++;

        s2 = ( (n-2.0) / (n-1.0) * s2)  + ( 1.0 / n) * pow(x - mean, 2.0);

        mean = sum / n;
    }

    printf("mean = %.2lf\nσ = %.2lf\n", mean, sqrt(s2));
}