C++中空指针可以调用成员函数，但是也要注意有没有用到this指针

  • 如果用到this指针，需要加以判断保证代码的健壮性

代码示例

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#include<iostream>
using namespace std;

class Person {
public:
	void showClassName() { //无this
		cout << "this is Person class" << endl;
	}

	void showPersonAge() { //有this
		cout << "age = "<< this->m_Age <<endl;
	}
	int m_Age;
};

int main() {
	Person* p = NULL;
	p->showClassName();//正常
	p->showPersonAge();//报错，因为传入指针为空（NULL）
	return 0;
}

解决方法

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#include<iostream>
using namespace std;

class Person {
public:
	void showClassName() {
		cout << "this is Person class" << endl;
	}

	void showPersonAge() {
		if (this == NULL) {
			return;
		}
		cout << "age = "<< this->m_Age <<endl;
	}
	int m_Age;
};

int main() {
	Person* p = NULL;
	p->showClassName();
	p->showPersonAge();
	return 0;
}