C++ Supplementary

头文件

1
2
3
4
5
6
7
8
9
10
11
12
13
// MyHeader.h
#ifndef CLIONTEST_MY_HEADER_H
#define CLIONTEST_MY_HEADER_H

#include <iostream>

using namespace std;

extern int x;

void f();

#endif

aux.cpp

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
// aux.cpp
#include "MyHeader.h"

void f() {
    cout << "x is " << x << endl;
}

/*
 * main.o ------------
 * int x;
 * int main();
 *
 * aux.o --------------
 * extern int x;
 * void f(); ---> uses x
 */

###main.cpp

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
// main.cpp
#include <iostream>

using namespace std;

int main() {
    cout << "this is out" << endl;
}

/*
 *     stdin    +-----+   stdout
 * ===========->| cpp |===========->
 *              +-----+
 *
 * I/O: In/Out
 */