fgets inside the while loop

Question

I'm having an issue with fgets because it is returning \n on the first time it enters the while loop right after the k input. Since I'm already inside the while loop and my #1 try as already been written, how do I deal with this?

int main() {
    char r;

    printf("How to input?\n");
    printf("Keyboard ([K])\n File ([F])\n Leave ([E])\n");
    scanf("%c", &r);

    if (r == 'k' || r == 'K') {
        printf("\nKeyboard\n");
        opcaoTeclado();
    } else {
       // stuff
    }
}

void opcaoTeclado() {
    int try = 0;
    char inputline[161];

    while (try <= 10) {
        printf("\n#%d try\n ", try);
        fgets(inputline, 160, stdin);
        try++;
    }
}

Answer 1

After the call to scanf(), there's a newline in the input which is read by the first call fgets(). fgets() stops reading input when it encounters a newline \n. Hence, it doesn't read any input.

Add a call to getchar(); right after scanf() to consume the newline.

Or you can also use a loop to consume if there are multiple chars in the input.

int c;

while((c= getchar()) != '\n' && c != EOF); 

In general, it's best to avoid mixing scanf() with fgets(). You can use fgets() instead of scanf() and parse the line using sscanf() which is less prone.