nmagerko nmagerko - 1 month ago 3x
C Question

How do I properly compare strings in C?

I am trying to get a program to let a user enter a word or character, store it, and then print it until the user types it again, exiting the program. My code looks like this:

#include <stdio.h>

int main()
char input[40];
char check[40];
int i=0;
printf("Hello!\nPlease enter a word or character:\n");
printf("I will now repeat this until you type it back to me.\n");

while (check != input)
printf("%s\n", input);

printf("Good bye!");

return 0;

The problem is that I keep getting the printing of the input string, even when the input by the user (check) matches the original (input). Am I comparing the two incorrectly?


You can't (usefully) compare strings using != or ==, you need to use strcmp:

while (strcmp(check,input) != 0)

The reason for this is because != and == will only compare the base addresses of those strings. Not the contents of the strings themselves.