c++ 链接

header.h

#ifndef HEADER_H
#define HEADER_H
unsigned long getFac(unsigned short num);
static const unsigned short headerNum = 5;


#endif // HEADER_H_INCLUDED

this.cpp

#include "header.h"
#include <iostream>
using namespace std;

extern unsigned short thatNum; //声明thatNum是来自外部的
static bool printMe = false;

int main()
{

    unsigned short thisNum = 10;
    cout <<  thisNum << "i = " << getFac(thisNum) << endl;
    cout <<  thatNum << "i = " << getFac(thatNum) << endl;
    cout <<  headerNum << "i = " << getFac(headerNum) << endl;
    if(printMe)
    {
        cout << "that.cpp -> printMe = true 发挥作用" << endl;
    }
    else
    {
        cout << "this.cpp -> static boolean printMe 发挥作用" << endl;
    }
    return 0;
}

that.cpp

#include "header.h"

unsigned short thatNum = 8;
bool printMe = true;

unsigned long getFac(unsigned short num)
{
    unsigned long sum = 1;
    for (int i=1; i<=num; i++)
    {
        sum *= i;
    }
    if(printMe)
    {
        return sum;
    }
    else
    {
        return 0;
    }
}