C++11之nullptr

我经常在代码中使用诸如一下代码来给指针变量赋值：

char *buf = NULL;

但是C++11已经摒弃了这种用法。因为这种用法会带来重载解析的麻烦，详见代码：

#include <iostream>

using namespace std;

void foo(char *);
void foo(int);

int _tmain(int argc, _TCHAR* argv[])
{
    if (is_same<decltype(NULL), decltype(0)>::value)
    {
        cout << "NULL == 0" << endl;
    }
    if (is_same<decltype(NULL), decltype((void*)0)>::value)
    {
        cout << "NULL == (void*)0" << endl;
    }
    if (is_same<decltype(NULL), nullptr_t>::value)
    {
        cout << "NULL == nullptr" << endl;
    }

    foo(0);
    foo(NULL);
    foo(nullptr);

    return 0;
}

void foo(char *)
{
    cout << "foo(char*) is called" << endl;
}

void foo(int i)
{
    cout << "foo(int) is called" << endl;
}

输出结果：

NULL == 0
foo(int) is called
foo(int) is called
foo(char*) is called

 

转载于:https://www.cnblogs.com/licb/p/8981090.html