设有如下代码，代码无法正常运行。请添加必要的成员函数使之能够正确运行。 #include <iostream> #include <string> using namespace std; class T { char *p1; public: T(char *s1=""); ~T(); void print() {cout<<"p1="<<p1<<endl;} }; T::T(char *s1) { p1=new char[strlen(s1)+1]; strcpy(p1,s1); } T::~T(){ delete [] p1;} int main() { T t1("Lucky boy"),t2(t1),t3; t1.print(); t2.print(); t3=t2=T("Welcome"); t2.print(); t3.print(); }

代码中缺少赋值运算符重载函数，需要添加以下成员函数：

T& operator=(const T& t) {
    if (this == &t) return *this;
    delete [] p1;
    p1 = new char[strlen(t.p1)+1];
    strcpy(p1, t.p1);
    return *this;
}

完整代码如下：

#include <iostream>
#include <string>
#include <cstring>
using namespace std;

class T {
    char *p1;
public:
    T(char *s1="");
    ~T();
    T& operator=(const T& t) {
        if (this == &t) return *this;
        delete [] p1;
        p1 = new char[strlen(t.p1)+1];
        strcpy(p1, t.p1);
        return *this;
    }
    void print() {cout<<"p1="<<p1<<endl;}
};

T::T(char *s1) {
    p1=new char[strlen(s1)+1];
    strcpy(p1,s1);
}

T::~T(){
    delete [] p1;
}

int main() {
    T t1("Lucky boy"),t2(t1),t3;
    t1.print();
    t2.print();
    t3=t2=T("Welcome");
    t2.print();
    t3.print();
    return 0;
}