c++ day4

#include <iostream>

using namespace std;
class stu
{
    friend const bool operator>(const stu &s1,const stu &s2);
    friend const bool operator<(const stu &s1,const stu &s2);
    friend const bool operator>=(const stu &s1,const stu &s2);
    friend const bool operator<=(const stu &s1,const stu &s2);
    friend const bool operator==(const stu &s1,const stu &s2);
    int a;
    int b;
public:
    stu(int a,int b):a(a),b(b)
    {
        cout << "有参构造" << endl;
    }

};
const bool operator>(const stu &s1,const stu &s2)//类外+号运算符重载 本质:s3=operator +(s1+s2)
{
    if(s1.a>s2.a&&s1.b>s2.b)
    {
        return true;
    }
    else
    {
        return false;
    }
 }
const bool operator<(const stu &s1,const stu &s2)//类外+号运算符重载 本质:s3=operator +(s1+s2)
 {
   if(s1.a<s2.a&&s1.b<s2.b)
   {
       return true;
   }
   else
   {
       return false;
   }

}
const bool operator>=(const stu &s1,const stu &s2)//类外+号运算符重载 本质:s3=operator +(s1+s2)
 {
   if(s1.a>=s2.a&&s1.b>=s2.b)
   {
       return true;
   }
   else
   {
       return false;
   }

}
const bool operator<=(const stu &s1,const stu &s2)//类外+号运算符重载 本质:s3=operator +(s1+s2)
 {
   if(s1.a<=s2.a&&s1.b<=s2.b)
   {
       return true;
   }
   else
   {
       return false;
   }

}
const bool operator==(const stu &s1,const stu &s2)//类外+号运算符重载 本质:s3=operator +(s1+s2)
 {
   if(s1.a==s2.a&&s1.b==s2.b)
   {
       return true;
   }
   else
   {
       return false;
   }

}
int main()
{
    stu s1(20,30);
    stu s2(20,20);
    if(s1>s2)
        cout << "s1>s2" << endl;
    else if(s1<s2)
        cout << "s1<s2" << endl;
    else if(s1==s2)
        cout << "s1==s2" << endl;
    else if(s1>=s2)
        cout << "s1>=s2" << endl;
    else if(s1<=s2)
        cout << "s1<=s2" << endl;
    else
        cout << "s1!=s2" << endl;

    return 0;
}