Getting Input with Scanf

Int

int main(void)
{
    int x;
    printf("x: ");
    scanf("%i", &x);
    printf("x: %i\n", x);
}

String

Non-functional:

int main(void)
{
    char *s;
    printf("s: ");
    scanf("%s", s);
    printf("s: %s", s);
}

• This just returns "s: null" because char *s needs dynamic memory allocation while int x has a fixed space in memory.

Possible fixes:

• Use memalloc(n), but then you run the risk of segfaulting on a large input.
• The cs50 library way, which is to call memalloc on every keystroke to dynamically allocate memory quite dynamically.