strcmp not working in while loop

What I want to do in my C code is to check for user input and validate that they can only type in either "one" or "two". I made a while loop that checks the user input value with strcmp, but it does not work. The while loop seem to be ignoring the getchar(); and going on an infinite loop.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

     int main ()
       {
        char choice[80];
        while(strcmp (choice,"one") != 0 || strcmp (choice,"two") != 0){
        scanf("%s", &choice);
        getchar();
        }
        // if the user enters either one or two, continue executing code...
       return 0;
     }

Solution

I saw 3 issues in your code:

1

while(strcmp (choice,"one") != 0 || strcmp (choice,"two") != 0)

This condition never evaluates to false. Because either the user enters one or two or aything else the any of the or both strcmp condition returns true.

2

 scanf("%s", &choice);

No need of & there. For reading string to an character array using %s you don't need to use & (because when you specify the name of character array the address is pointed).

Just write like:

scanf("%s", choice);

3

It's a logical one. You just declared an character array. And on the next line you are using it in strcmp. surely the array will have garbage values.

My solution:

Implement your code like:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main ()
{
   char choice[80];
   while(1)
   {
        scanf("%s", choice);
        if(strcmp (choice,"one") == 0 || strcmp (choice,"two") == 0)
        {
           break;
        }
        getchar();
   }
   // if the user enters either one or two, continue executing code...
   return 0;
}