//建立一个异常类来处理:在输入学生类stu对象的数据时，检测输入成绩是否正确     yes
#include<iostream.h>
#include<string.h>
class String
 {    public:
      String operator +(const String&);
   String operator =(const String&);
      void input();
   void print() const;
     private:
       char name[20];
 };
String String::operator +(const String& first)
{
String temp;
//strcat(temp.name,name);
strcat(temp.name,(first.name));
return temp;
}
String String::operator =(const String& first)
{
 for(int x=0;x<20;x++)
  name[x]=first.name[x];
    return *this;
}
void String::input()
{
 cout<<"输入字符串:"<<endl;
 cin>>name;
}
void String::print() const
{
cout<<name<<endl;
}
void main()
 {  String a,b,c;
    a.input();
     b.input();
    c=a+b;
    c.print();
    a=b;
    a.print();
 }            运行时候出了点问题

修改完毕~调试通过~

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#include<iostream.h> #include<string.h> class String { public: String operator +(const String); String operator =(const String); void input(); void print() const; private: char name[20]; }; String String::operator +(String c) { strcat(name, c.name); return *this; } String String::operator =(String c) { for(int x=0;x<20;x++) name[x]=c.name[x]; return *this; } void String::input() { cout<<"输入字符串:"<<endl; cin>>name; } void String::print() const { cout<<name<<endl; } void main() { String a,b,c; a.input(); b.input(); c=a+b; c.print(); a=b; a.print(); }