this

this#

this 是指向当前对象的指针,在类的非静态成员函数内部都可以使用。它的典型用途有:

  • 区分同名变量:当成员函数参数与成员变量重名时,用 this->member 指代成员变量(见下方 setBorn());

  • 返回对象自身:链式调用(如 obj.setA().setB())时 return *this

  • 在构造函数中调用其他成员函数:明确表示”调用的是这个对象的成员”(见下方带参构造函数)。

注意:this 只在非静态成员函数中有效,静态成员函数没有 this 指针。

#include <cstring>
#include <iostream>

using namespace std;

class Student {
private:
    char* name;
    int born;
    bool male;

public:
    Student() {
        name = new char[1024]{0};
        born = 0;
        male = false;
        cout << "Constructor: Person()" << endl;
    }

    Student(const char* name, int born, bool male) {
        this->name = new char[1024];
        this->setName(name);
        this->born = born;
        this->male = male;
        cout << "Constructor: Person(const char, int , bool)" << endl;
    }

    ~Student() {
        cout << "To destroy object: " << name << endl;
        delete[] name;
    }

    void setName(const char* name) { strncpy(this->name, name, 1024); }

    void setBorn(int born) { this->born = born; }

    // the declarations, the definitions are out of the class
    void setGender(bool isMale);
    void printInfo();
};

void Student::setGender(bool isMale) {
    male = isMale;
}

void Student::printInfo() {
    std::cout << "Name: " << name << std::endl;
    std::cout << "Born in " << born << std::endl;
    std::cout << "Gender: " << (male ? "Male" : "Female") << std::endl;
}

int main() {
    Student* class1 = new Student[3]{
        {"Tom", 2000, true},
        {"Bob", 2001, true},
        {"Amy", 2002, false},
    };

    class1[1].printInfo();
    delete[] class1;

    return 0;
}