C function call selection using ternary operator

Question

I have two C functions f1 and f2 that take the same arguments. Based on a condition, I need to invoke one or the other one with the same arguments:

if (condition) {
    result = f1(a, b, c);
} else {
    result = f2(a, b, c);
}

I understand it is possible to use the syntax:

result = condition ? f1(a, b, c) : f2(a, b, c)

Is it be possible to have a DRY syntax that requires to write arguments a single time?

Answer 1

Yes, it works fine just like you suggested.

The function call operator () just needs a left-hand-side that evaluates to a function pointer, which names of functions do.

There's no need to derefence function pointers when calling, the () operator does that.

This sample program demonstrates:

#include <stdio.h>

static int foo(int x) {
    return x + 1;
}

static int bar(int x) {
    return x - 1;
}

int main(void) {
    for (int i = 0; i < 10; ++i)
        printf("%d -> %d\n", i, (i & 1 ? foo : bar)(i));
    return 0;
}

It prints:

0 -> -1
1 -> 2
2 -> 1
3 -> 4
4 -> 3
5 -> 6
6 -> 5
7 -> 8
8 -> 7
9 -> 10

There is nothing strange here.

And since C predates Python by a fair bit, perhaps it's Python's semantics that are C-ish here. Or just plain sane, of course. :)