#include "functions.h"

void functionB() {} // declared & defined
void functionC(); // declared
void functionD(); // declared

int main()
{
    // functionA(); // compiler error, because functionA is declared & defined after it is called
    functionB(); // no error
    // functionC(); // linker error, because functionC is declared but not defined
    functionD(); // no error
    functionE(); // no error

    return 0;
}

void functionA() {} // declared & defined

void functionD() {} // defined

// void functionE() {} // linker error, because functionE is defined multiple times