不同作用域中的静态和全局变量

Question

我是一个程序员初学者...这里我有一段代码有两个函数...其中一个使用全局变量，而另一个使用局部静态变量...

下面是代码：

//Scope Rules
#include <iostream>
using namespace std;

int num {52};     //Global Variable - Declared outside any class or function

void globalExample();
void staticLocalExample();

void globalExample(){
    cout << "\nGlobal num in globalExample is: " << num << " - start" << endl;
    num *= 4;
    cout << "Global num in globalExample is: " << num << " - end" << endl;
}
void staticLocalExample(){
    static int num {5};      //local to staticLocalExample - retains it's value between calls
    cout << "\nLocal static num in staticLocalExample is: " << num << " - start" << endl;
    num += 20;
    cout << "Local static num in staticLocalExample is: " << num << " - end" << endl;
}

int main() {

    globalExample();
    globalExample();
    staticLocalExample();
    staticLocalExample();

    return 0;
}

我两次调用这些函数的原因是为了让我明白，第二次调用该函数时，更改将存储到变量中，因此结果将不同。

null

Answer 1

我想我得出结论了...所以如果我错了请告诉我...

Global varialble：您可以更改它们，并在其作用域之外或内部分配不同的数字

静态变量：只能在其范围内更改，不能在其范围外更改

#include <iostream>
using namespace std;

int num {52};     //Global Variable - Declared outside any class or function

void globalExample();
void staticLocalExample(int x);

void globalExample(){
    cout << "\nGlobal num in globalExample is: " << num << " - start" << endl;
    num *= 4;
    cout << "Global num in globalExample is: " << num << " - end" << endl;
}
void staticLocalExample(int x){
    static int num {5};      //local to staticLocalExample - retains it's value between calls
    cout << "\nLocal static num in staticLocalExample is: " << num << " - start" << endl;
    num += 20;
    cout << "Local static num in staticLocalExample is: " << num << " - end" << endl;
}

int main() {

    globalExample();
    num = 20;
    globalExample();
    staticLocalExample(10);
    staticLocalExample(15);

    return 0;
}

Global num in globalExample is: 52 - start
Global num in globalExample is: 208 - end

Global num in globalExample is: 20 - start     <-------
Global num in globalExample is: 80 - end

Local static num in staticLocalExample is: 5 - start
Local static num in staticLocalExample is: 25 - end

Local static num in staticLocalExample is: 25 - start
Local static num in staticLocalExample is: 45 - end