Declaring and calling functions

We already know one function: int main(). So far, we have put most of our code there. As a program grows, however, we may need to perform the same work more than once. Copying and pasting the same statements makes the code harder to maintain.

Instead, we can declare another function. Here is a simple example using void test():

#include <stdio.h>

void test()
{
    printf("Hello");
}

int main()
{
    test();
    return 0;
}

The program defines a function named test. Inside main, the call test(); runs the statements inside that function, printing Hello.

This lets us give a reusable block of work a name and call it whenever we need it.