C Program Gives Results After I Stop It

Question

So, right now I've been learning function pointers and the code I've written for it is below

#include <stdio.h>
#include <stdlib.h>

void addition(int a, int b) {
    printf("%d", a + b);
}
void subtraction(int a, int b) {
    printf("%d", a - b);
}
void multiplication(int a, int b) {
    printf("%d", a * b);
}
void division(int a, int b) {
    printf("%d", a / b);
}

int main() {
    void (*functionPTR_ARR[])(int, int) = { addition, subtraction, multiplication, division };
    unsigned int ch, a = 15, b = 10;

    printf("Enter a Array Number: ");
    scanf("%d\n", &ch);

    (*functionPTR_ARR[ch])(a, b);
}

When I run the program and give it input, let's say 2, for the multiplication function. It'll run but it won't give the results while running, it will only give them when I stop it. Is there a reason why this is happening?

Because the output buffer is not being flushed to the display device. There are no newlines or `fflush` statements. But when a program ends, its output buffers are flushed automatically. But strangely, you have one in `scanf("%d\n", &ch);` where it is not usually desirable. — Weather Vane, May 07 '20 at 17:45
Ah ok! I've put in `fflush(ch);` and it nows works perfectly! Thanks for the advice! — The Programming M16A4, May 07 '20 at 20:29
You need `fflush(stdout)`. You should have got a compiler warning, and, it's always worth reading up on the functions you use. Don't guess. — Weather Vane, May 07 '20 at 20:42
In that case you need to *enable* full warnings with `-Wall`. — Weather Vane, May 08 '20 at 15:41
Let me guess, I need to write that every time I want to build a file in my gcc commands? — The Programming M16A4, May 08 '20 at 16:28
Actually I am surprised that you did not get a warning, since passing an incompatible type usually generates one. I don't have a system with gcc up at the mo so can't check it out. — Weather Vane, May 08 '20 at 16:32

C Program Gives Results After I Stop It

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