Question

I made a while loop inside a program and the program reaches the while loop, but it doesn’t execute. I feel like there’s a really tiny error that I’m missing since I’ve been looking at the code for so long.

  int strbuf = 100;
  char string[strbuf];
  char *exit = "exit";
  while(!strcmp(string, exit)){
      printf("Enter a word to search. Enter exit to quit");
      scanf("%s", string);
      state = present(fIndex, string);
      if(state){
        printf("The word %s was found on line %d", string, state);
    }
}

EDIT: the input is from the keyboard.
EDIT EDIT: NEW CODE (same problem)

int strbuf = 100;
char string[strbuf];
char *exit = "exit";

printf("Enter a word to search. Enter exit to quit\n");
scanf("%s", string);
    while(!strcmp(string, exit)){
    state = present(fIndex, string);
    if(state){
        printf("The word %s was found on line %d", string, state);
    }
    else printf("The word %s was not found", string);
}

Answer 1

Read the man page for strcmp:

The strcmp() function compares the two strings s1 and s2. It
returns
an integer less than, equal to, or greater than zero if s1 is found,
respectively, to be less than, to match, or be greater than s2.

If you have a match, strcmp will return 0, and if the two strings don’t match it’ll return a non-zero value.

Therefore while(!strcmp(string, exit)) is really saying, while the strings match, continue to loop.

string is also uninitialized and contains junk, causing undefined behaviour. Either initialise it first or or use a do..while loop if your loop must execute at least once.