[C++] 交换指针

编写一个函数，令其交换两个int指针。

交换两个值可以使用两种形式，一种是使用引用传递实参进行交换，另一种是使用指针以值传递的方式进行交换。

题目要求交换两个int指针，也可以参考交换值的两种形式。

1、使用指向指针的指针进行交换。

void swapPointerUsePointer(int **p, int **q)
{
    int *t = *p;
    *p = *q;
    *q = t;
}

2、使用引用来传递指针进行交换、

void swapPointerUseReference(int *&p, int *&q)
{
    int *t = p;
    p = q;
    q = t;
}

测试代码如下：

int main()
{
    int a = 100, *p = &a;
    int b = 200, *q = &b;
    cout << "original pointer and value: " << endl;
    cout << "a: " << p << " value: " << *p << endl;
    cout << "b: " << q << " value: " << *q << endl;
    cout << endl;
    cout << "after swap by pointer the current pointer and value: " << endl;
    swapPointerUsePointer(&p, &q);
    cout << "a: " << p << " value: " << *p << endl;
    cout << "b: " << q << " value: " << *q << endl;
    cout << endl;
    cout << "after swap by reference the current pointer and value: " << endl;
    swapPointerUseReference(p, q);
    cout << "a: " << p << " value: " << *p << endl;
    cout << "b: " << q << " value: " << *q << endl;
    cout << endl;
    return 0;
}

测试结果如下：

original pointer and value:
a: 006FF780 value: 100
b: 006FF768 value: 200

after swap by pointer the current pointer and value:
a: 006FF768 value: 200
b: 006FF780 value: 100

after swap by reference the current pointer and value:
a: 006FF780 value: 100
b: 006FF768 value: 200