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2017-07-25T20:27:27+00:00
C/C++ 中的 extern 的變數範例
資料來源: https://medium.com/@alan81920/c-c-中的-static-extern-的變數-9b42d000688f
CodeBlocks 12.11
module1.cpp
#include
#include "module1.h"
using namespace std;
int a = 1;
void greeting() {
cout << "Hello World!" << endl;
cout << "In greeting, a = " << a << endl;
}
module1.h
#ifndef MODULE1_H_INCLUDED
#define MODULE1_H_INCLUDED
extern int a;
void greeting();
#endif // MODULE1_H_INCLUDED
main.cpp:
#include
#include "module1.h"
using namespace std;
int main() {
greeting();
cout << "In main, a = " << a << endl;
cout << endl;
a = 0;
cout << "In main, a = " << a << endl;
greeting();
return 0;
}
/*
Hello World!
In greeting, a = 1
In main, a = 1
In main, a = 0
Hello World!
In greeting, a = 0
*/
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