在这种情况下，如何包含所有.cpp和头文件？

Question

So, say I have something like this:

main.cpp

#include "main.h"

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

main.h

#include <stdio.h>
#include <iostream>

display.cpp

#include "display.h"

void displayMessage() {
    std::cout << "HELLO!\n";
}

display.h

void displayMessage();

How could I include all of them together without being deeply nested? I just started programming a week ago and trying to start early before college starts this upcoming Fall.

Answer 1

First giving main a header just to include its headers is a little over the top so I would avoid that.

Something like this:

main.cpp

#include <cstdio>
#include <iostream>

#include "display.h"

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

display.cpp

#include "display.h"

void displayMessage() {
    std::cout << "HELLO!\n";
}

display.h

// prevent including the same header twice
#ifndef MY_PROJECT_DISPLAY_H
#define MY_PROJECT_DISPLAY_H

void displayMessage();

#endif // MY_PROJECT_DISPLAY_H

Then compile each .cpp file to an object file:

g++ -c -o main.o main.cpp
g++ -c -o display.o display.cpp

Then link the objects to make an executable:

g++ -o my_program_name main.o display.o

You may want to set some useful flags while compiling (highly recommended):

g++ -std=c++14 -Wall -Wextra -pedantic-errors -c -o main.o main.cpp
g++ -std=c++14 -Wall -Wextra -pedantic-errors -c -o display.o display.cpp

Answer 2

Its better if you don't create and include main.h in main.cpp . Instead include display.h in main.cpp .

Also "Modern C++" encourages to use C++ style include headers <cstdio> instead of C style ones stdio.h .

And yes, welcome to programming. It's fun. :)