#include <iostream>
#include <string>
using namespace std;

//值傳遞:（傳值調用）
//效果上：方法內的改變不會影響到方法外
//本質上：只改變了形參的值，並沒有改變實參的值
//條件上：形參的類型為基本類型或者一般復雜類型
void swap(int num1,int num2)    //傳值調用
{
    int temp;
    temp = num1;
    num1 = num2;
    num2 = temp;
    cout << "swap: " << num1 << "
 
 " << num2 << endl;
}

//引用傳遞：(地址傳遞)(傳址調用)
//效果上：方法內的改變會影響到方法外
//本質上：通過形參指針去改變了實參的值
//條件上：形參為指針和數組和引用時一般都是引用傳遞,（特殊情況:當函數內只改變了指針的指向，而沒有通過指針去修改實參值時,仍然是傳值調用）
void swap_point(int *num1,int *num2)    //傳址調用
{
    int temp;
    temp = *num1;
    *num1 = *num2;
    *num2 = temp;
    cout << "swap_point:
 
" << *num1 << " " << *num2 << endl;
}

void swap_value(int *num1,int *num2)    //傳值調用
{
    int *temp;
    temp = num1;
    num1 = num2;
    num2 = temp;
    cout << "swap_value :" << *num1 << " " << *num2 << endl;
}

void swap_two(int **num1,int **num2)    //
 
傳址調用
{
    int *temp = NULL;
    temp = *num1;
    *num1 = *num2;
    *num2 = temp;
    cout << "swap_two: " << **num1 << " " << **num2 << endl;
}

void swap_ref(int &num1,int &num2)      //傳址調用
{
    int temp;
    temp = num1;
    num1 = num2;
    num2 = temp;
    cout << "swap_ref " << num1 << " " << num2 << endl;
}

int main()
{
    int a = 10,b = 20;
    cout << "a = " << a << "b = " << b << endl;
#if 0
    swap(a,b);
#endif

#if 0
    swap_point(&a,&b);
#endif

#if 0
    swap_value(&a,&b);
#endif

#if 0
    int *p1 = &a,*p2 = &b;
    cout << *p1 << " " << *p2 << endl;
    swap_two(&p1,&p2);
    cout << "a = " << *p1 << "b = " << *p2 << endl;
#endif

    swap_ref(a,b);
    cout << a << " " << b << endl;
}

值傳遞和（地址）引用傳遞