//31用复制构造函数实现字符串的初始化/*#include 
     
      using namespace std;class String{public:	String(); //默认的构造函数	String(const char*const ch); //构造带值的string	int getlen()const { return len;}   //读取长度	const char *getstr()const{ return str;} //读取字符串	//这里是可以修改的	char &operator[](unsigned short int  length);	char  operator[](unsigned short int  length)const;	//复制构造函数	String (const String&r);private:	unsigned short int len;	char *str;};//创建一个空的str变量String::String(){    len = 0;	str = new char[1];	str[0] = '\0';};String::String(const char*const ch){	cout<<"带一个参数的构造函数"<
      
        len){		   return str[len-1]; //返回可见字符的值		}else{		   return str[length];		}};char String::operator[](unsigned short int length)const{	    cout<<"下标运算符const执行"<
       
         len){		   return str[len-1]; //返回可见字符的值		}else{		   return str[length];		}};String::String (const String&rs){	len = rs.getlen();	str = new char[len+1];	for(int i=0; i
        
         >s3[999];	cout<
         
          <
          
           using namespace std;class A{public: A(int i, int j){ x=i; y=j;} void set(int s1, int s2){ x=s1; y=s2;} void print(){cout<
           
            <