fgets cutting off input after 3rd character

Asked Feb 08 '21 at 16:16

Active Feb 08 '21 at 16:16

Viewed 33 times

I have a function to take in and format user input, but it keeps cutting off the input after the 3rd character.

void formatInput(char *input_variable) {
    fgets(input_variable, sizeof(input_variable), stdin);
    strtok(input_variable, "\n");
}

int main() {
    char input_string[255];
    printf("Enter input: ");
    formatInput(&input_string[0]);

   return 0;
}

If I enter myinput then it gets stored as myi. If I don't wrap it in this function, then it works perfectly fine.

asked Feb 08 '21 at 16:16

Phoenix

3

`gets(input_variable, sizeof(input_variable), stdin);` sizeof will yield the size of a **pointer**. (which appears to be 4 on your machine) – wildplasser Feb 08 '21 at 16:18
@wildplasser Am I not passing the same value to `fgets` in that function as I would if I were to call it in `main()` then? I thought they would both be the address of the first element of the array. How would I get the size of the entire array from within the function then? – Phoenix Feb 08 '21 at 16:21
Ooops, the `f` fell off while cut&pasting ... – wildplasser Feb 08 '21 at 16:25
1

As seen by the function, there is no array. The only thing the function can see is the pointer. Which could basically point to *anything*, even a single character. Or it could be NULL. The function cannot tell. – wildplasser Feb 08 '21 at 16:28
2

You must pass the size of the array to your function. – M. Nejat Aydin Feb 08 '21 at 16:31
@wildplasser Ah I see. That makes sense. – Phoenix Feb 08 '21 at 16:32
@M.NejatAydin I'll do this then. Thanks! – Phoenix Feb 08 '21 at 16:33
BTW the `strtok(input_variable, "\n");` does nothing; you are not using its return value. – wildplasser Feb 08 '21 at 16:34
@wildplasser I don't need its return value. It's still modifying my original string and removing the newline. – Phoenix Feb 08 '21 at 16:42
You are correct. – wildplasser Feb 08 '21 at 16:44

fgets cutting off input after 3rd character

0 Answers0