2022-11-7 c++

#include <iostream>
#include <string>
using namespace std;
class student
{
private:
    char *str;
    int len;
public:
    student(){}//无参构造函数
    ~student(){}//析构函数
    student(char *p)//有参构造函数
    {
        len=my_size(p);
        str=new char[len];
        for(int i=0;i<len;i++)
        {
            str[i]=*(p+i);
        }
    }
    student(student& s)//拷贝构造函数
    {
        this->len=s.len;
        str=new char[len];
        for(int i=0;i<len;i++)
        {
            str[i]=s.str[i];
        }
    }
    student& operator=(student &R)
    {
        this->len=R.len;
        this->str=new char[len];
        for(int i=0;i<len;i++)
        {
            str[i]=R.str[i];
        }
        return *this;
    }
    
    const student operator+(const student& R)const//+
    {
        student tem;
        R.len=my_size(R.str);
        tem.len=this->len+R.len;
        tmp.str=new char[temp.len];
        for(int i=0;i<tmp.len;i++)
        {
            if(i<this->len)
            {
                tmp.str[i]=R.str[i-(this->len)];
            }
        }
        return tmp;
    }
    
    bool operator ==(student&S)//==
    {
        for(int i=0;i<len;i++)
        {
            if(str[i]!=S.str[i])
            {
                break;
            }
            
        }
        if((this->len==S.len)&&(i==this->len))
        {
            return 1;
        }
        else
        {
            return 0;
        }
        
        bool operator >(student&S)//>
        {
            for(i=0;i<len;i++)
            {
                if(str[i]!=S.str[i])
                {
                    break;
                }
                
            }
            
            if((this->len==S.len)&&(i==this->len))
            {
                return 1;
            }
            else
            {
                return 0;
            }
            
            bool operator <(student&S)//<
            {
                for(i=0;i<len;i++)
                {
                    if(str[i]!=S.str[i])
                    {
                        break;
                    }
                    
                }
                
                if((this->len==S.len)&&(i==this->len))
                {
                    return 1;
                }
                else
                {
                    return 0;
                }
                bool operator >=(student&S)//>=
                {
                    for(i=0;i<len;i++)
                    {
                        if(str[i]!=S.str[i])
                        {
                            break;
                        }
                        
                    }
                    
                    if((this->len==S.len)&&(i==this->len))
                    {
                        return 1;
                    }
                    else
                    {
                        return 0;
                    }
                    
                    bool operator <=(student&S)//<=
                    {
                        for(i=0;i<len;i++)
                        {
                            if(str[i]!=S.str[i])
                            {
                                break;
                            }
                            
                        }
                        
                        if((this->len==S.len)&&(i==this->len))
                        {
                            return 1;
                        }
                        else
                        {
                            return 0;
                        }
                        
                        bool operator !=(student&S)//!=
                        {
                            for(i=0;i<len;i++)
                            {
                                if(str[i]!=S.str[i])
                                {
                                    break;
                                }
                                
                            }
                            
                            if((this->len==S.len)&&(i==this->len))
                            {
                                return 1;
                            }
                            else
                            {
                                return 0;
                            }
                            
                            
                            
                            void show()
                            {
                                cout<<"str="<<this->str<<endl;
                            }
                            
                            int my_size(char *s)//长度
                            {
                                int len=0;
                                while(*s!='\0')
                                {
                                    len++;
                                    s++;
                                }
                                return len+1;
                            }
                            
                            bool my_empty()  //判空
                            {
                                return len==0?true:false;
                            }
                        };
                        
                        int main()
                        {
                            student s1("hello");
                            s1.show();
                            student s2(s1);
                            s2.show();
                            student s3;
                            s3=s2;
                            s3.show();
                            if(s1.my_empty()==true)
                            {
                                cout<<"null"<<endl;
                            }
                            else
                            {
                                cout<<"full"<<endl;
                            }
                            student s4("hello");
                            cout<<(s1==s4?"yes":"no")<<endl;
                            cout<<(s1>s4?"yes":"no")<<endl;
                            cout<<(s1<s4?"yes":"no")<<endl;
                            cout<<(s1>=s4?"yes":"no")<<endl;
                            cout<<(s1<=s4?"yes":"no")<<endl;
                            cout<<(s1!=s4?"yes":"no")<<endl;
                            student s5;
                            s5=s1+s4;
                            s5.show();
                            
                            return 0;
                        }