Question

I have the following code:

int main() {
    char *sPPhrase[51];

    /* Input */
    printf("Enter string (max. 50 chars):\n");
    fflush(stdout);                         /* Works around an annoying Eclipse bug that fails to display the output from the printf command */
    scanf("%s", *sPPhrase);   /* Won't work */

    /* More code goes here */
}

The scanf() command fails, I assume, because *sPPhrase is not writable as sPPhrase points to a string constant. The compiler doesn’t have a clue of anything being wrong. A little later on, I need to pass this string to this function:

char* reverse(char* sPPhrase[]);

The string constant is not writable, but I need to pass this char* on to this function. How do I rewrite my code to make it work?

Answer 1

You are declaring an array of pointers, not a array of chars (commonly used as a string).

You need to declare like this:

char sPPhase[51];

Also, sscanf can get you in trouble: it’s better to use fgets to read a string in a bounded buffer:

int main() {
    char sPPhrase[51];
    printf("Enter string (max. 50 chars):\n");
    fflush(stdout);
    fgets(sPPhrase, 50, stdin);  // leave one byte for '\0'

    // More code
}

I don’t know what ‘reverse’ is doing, but you should probably define it as:

char* reverse(char* sPPhrase);

If it is doing the operation in place, you don’t even need a return value. If you do, don’t forget to free it when you are done.