Call a method without calling it
C

#include &lt;stdio.h&gt;

int puts(const char *str) {
  fputs("Hello, world!\n", stdout);
}

int main() {
  printf("Goodbye!\n");
}


When compiled with GCC, the compiler replaces printf("Goodbye!\n") with puts("Goodbye!"), which is simpler and is supposed to be equivalent. I've sneakily provided my custom puts function, so that gets called instead.