Calculating the square root

/* Calculating the square root by iterations */

#include <stdio.h>

int main(void) {
    double num = 570.15;
    double root = num / 2;
    double eps = 0.01;
    int iter = 0;
    while( root - num / root > eps ){
        iter++;
        root = 0.5 * (root + num / root);
        printf("Iteration: %d : root = %f\n", iter, root);
    }
    printf("root = %f", root);
    return 0;
}