#include "stdio.h" int main() { double a; double x=1.0; printf("please input a double\n"); scanf("%lf",&a); if (a<0) return 0; else while(x*x-a<-0.000001||x*x-a>0.000001) { x=(a/x+x)/2.0; } printf("%lf\n",x); return 1; }