参照我的上一个问题，试定义一个CString的子类CString2（可对CString声明做少量调整）,CString2声明如下： class CString2 :public CString { public: CString2(); //构造函数 CString2(const char s[]); //构造函数 CString2(CString2& t); //拷贝构造函数 CString2 &Cat(CString2&t); //字符串连接 int Cmp(CString2& t); //字符串比较 }; 在如下主函数中对该类进行测试。 int main() { char s0[100], s1[100]; cin >> s0 >> s1; CString2 cs0(s0),cs1(cs0); cs0.Set(s1); cout << cs0.Cmp(cs1) << endl; CString2 &t=cs0.Cat(cs1); t.Print(); return 0; } 输入输出示意如下： ASDF BSDF 1 BSDFASDF 请在答题窗口录入编写的完整程序。

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

class CString {
    private:
        char* str;
    public:
        CString();
        CString(const char s[]);
        CString(CString& t);
        ~CString();
        void Set(const char s[]);
        void Print();
};

CString::CString() {
    str = new char[1];
    str[0] = '\0';
}

CString::CString(const char s[]) {
    str = new char[strlen(s) + 1];
    strcpy(str, s);
}

CString::CString(CString& t) {
    str = new char[strlen(t.str) + 1];
    strcpy(str, t.str);
}

CString::~CString() {
    delete[] str;
}

void CString::Set(const char s[]) {
    delete[] str;
    str = new char[strlen(s) + 1];
    strcpy(str, s);
}

void CString::Print() {
    cout << str << endl;
}

class CString2 :public CString {
    public:
        CString2();
        CString2(const char s[]);
        CString2(CString2& t);
        CString2& Cat(CString2&t);
        int Cmp(CString2& t);
};

CString2::CString2() {}

CString2::CString2(const char s[]) :CString(s) {}

CString2::CString2(CString2& t) :CString(t) {}

CString2& CString2::Cat(CString2&t) {
    char* temp = new char[strlen(str) + strlen(t.str) + 1];
    strcpy(temp, str);
    strcat(temp, t.str);
    delete[] str;
    str = temp;
    return *this;
}

int CString2::Cmp(CString2& t) {
    return strcmp(str, t.str);
}

int main() {
    char s0[100], s1[100];
    cin >> s0 >> s1;
    CString2 cs0(s0), cs1(cs0);
    cs0.Set(s1);
    cout << cs0.Cmp(cs1) << endl;
    CString2& t = cs0.Cat(cs1);
    t.Print();
    return 0;
}