#include <stdio.h>

// Function declarations
void sayHello(void);
void sayBye(void);
void sayThanks(void);

int main() {
    // Declare a function pointer to a function with no parameters and no return value
    void (*funcPtr)(void);

    // Assign and call different functions using the pointer
    funcPtr = sayHello;
    funcPtr();   // Calls sayHello()

    funcPtr = sayThanks;
    funcPtr();   // Calls sayThanks()

    funcPtr = sayBye;
    funcPtr();   // Calls sayBye()

    return 0;
}

// Function definitions
void sayHello(void) {
    printf("Hello!\n");
}

void sayThanks(void) {
    printf("Thank you!\n");
}

void sayBye(void) {
    printf("Goodbye!\n");
}