why it does not work?

#include "stdafx.h"
#include <stdio.h>

int main(int argc, char* argv[])
{
double n;
double m;
n=0;
m=0;
do
scanf("%f", &n);
while(n != 0);
m = 1 / n;
printf("%g", m);

return 0;
}


n=0;
m = 1 / n;