#include "stdio.h"
#include "math.h"
int main()
{
    double a, x0, x1;
    printf("Input a:n");
    scanf("%lf", &a);
    if (a<0)
    {
        printf("Error!n");
    }
    else
    {
        x0 = a / 2;
        x1 = (x0 + a / x0) / 2;
        do 
        {
            x0 = x1;
            x1 = (x0 + a / x0) / 2;
        } while (fabs(x0-x1)>pow(10,-6));
    }
    printf("Result:n");
    printf("sqrt(%g)=%gn", a, x1);
    system("pause");
    return 0;
}