C Function Pointer Alternate Syntax

function_pointers.c

// compiled with:
// clang -Wall -Wextra function_pointers.c -o function_pointers
#include "stdio.h"

void usual_syntax (void (*fn) (int x)) {
  puts("usual syntax start");
  fn(1);
  puts("usual syntax end");
}

void other_syntax (void fn (int x)) {
  puts("other syntax start");
  fn(2);
  puts("other syntax end");
}

void hello (int x) {
  printf("hello %d\n", x);
}

int main () {
  puts("hello world");
  usual_syntax(hello);
  other_syntax(hello);
}