如何判断一个变量是不是指针

1.编写一个程序判断一个变量是不是指针？

拾遗
-C++中仍然支持C语言中的可变参数函数
-C++编译器的匹配调用优先级
1.重载函数
2.函数模板
3.变参函数

 

 

 

 

#include <iostream>
#include <string>

using namespace std;

class Test
{
public:
    Test()
    {
    }
    virtual ~Test()
    {
    }
};

template
<typename T>
bool IsPtr(T* v) // match pointer
{
    return true;
}

bool IsPtr(...)  // match non-pointer
{
    return false;
}


int main(int argc, char *argv[])
{
    int i = 0;
    int* p = &i;

    cout << "p is a pointer: " << IsPtr(p) << endl;    // true
    cout << "i is a pointer: " << IsPtr(i) << endl;    // false

    Test t;
    Test* pt = &t;

    cout << "pt is a pointer: " << IsPtr(pt) << endl;    // true
    cout << "t is a pointer: " << IsPtr(t) << endl;    // false

    return 0;
}

 

 

#include <iostream>
#include <string>

using namespace std;

class Test
{
public:
    Test()
    {
    }
    virtual ~Test()
    {
    }
};

template
<typename T>
char IsPtr(T* v) // match pointer
{
    return 'd';
}

int IsPtr(...)  // match non-pointer
{
    return 0;
}

#define ISPTR(p) (sizeof(IsPtr(p)) == sizeof(char))

int main(int argc, char *argv[])
{
    int i = 0;
    int* p = &i;

    cout << "p is a pointer: " << ISPTR(p) << endl;    // true
    cout << "i is a pointer: " << ISPTR(i) << endl;    // false

    Test t;
    Test* pt = &t;

    cout << "pt is a pointer: " << ISPTR(pt) << endl;    // true
    cout << "t is a pointer: " << ISPTR(t) << endl;    // false

    return 0;
}

 

分类: C++