1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | #include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
void say_hi() {
printf("Hi\n");
}
void say_bye() {
printf("Bye\n");
}
void say_something(void(*say_fn)()) {
// ▼ ▼ └───> types of parameters that say_fn takes
// «type fn returns» «name of parameter»
say_fn();
}
int main(int argc, char* argv[]) {
// Declare a variable called 'fn_to_say_something'.
// ∙ The type of 'fn_to_say_something' is "address of a function returning
// void and taking no parameters."
// ∙ Initialize 'fn_to_say_something' to the address of function say_hi(…).
void (*fn_to_say_something)() = say_hi;
// Call say_something(…), passing fn_to_say_something, which is currently set to the
// address of say_hi(…).
say_something( fn_to_say_something );
// Set fn_to_say_something to the address of say_bye(…).
fn_to_say_something = say_bye; // fn_to_say_something is now address of say_bye(…).
// Call say_something(…), passing fn_to_say_something, which is now set to the
// address of say_bye(…).
say_something( fn_to_say_something );
return EXIT_SUCCESS;
}
/* vim: set tabstop=4 shiftwidth=4 fileencoding=utf-8 noexpandtab: */
|
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