#include <stdio.h>


// Define a function that takes two integers as arguments and returns their sum

int add(int a, int b) {

    return a + b;

}


// Define a function that takes no arguments and returns nothing

void print_hello(void) {

    printf("Hello, world!\n");

}


int main(void) {

    // Call the add function and print the result

    int result = add(3, 4);

    printf("The sum of 3 and 4 is %d\n", result);


    // Call the print_hello function

    print_hello();


    return 0;

}

This program defines two functions: add, which takes two integers as arguments and returns their sum, and print_hello, which takes no arguments and returns nothing. It then calls these functions from the main function and prints the result of the add function to the console.

Here is an example of the output of this program:

The sum of 3 and 4 is 7
Hello, world!