Question

can someone explain what is going on inside the strcut? c++

struct Pos{
int x;
int y; // coordinates
Pos(const Pos &p, int dx=0, int dy=0){ *this = p; x+=dx; y+=dy;}
  
Pos(int _x, int _y){ x=_x; y=_y; } //new location
  
bool operator<(const Pos & p) const { return (x < p.x) || (x==p.x && y < p.y); }
  
  
bool operator==(const Pos & p) const { return x==p.x && y==p.y; }
Pos(){x=-1;y=-1;}
};

Answer 1

//do comment if any problem arises
//You has to have some knowledge of object oriented programming
// in order to fully understand this Code
#include <iostream>
using namespace std;
struct Pos
{
   // coordinates
   int x;
   int y;
   //this is constructor of structure Pos which takes another Pos and assigns it to current Pos
   //and then it takes one x and y value and increement x and y of current pos by respective values
   //of x and y
   Pos(const Pos &p, int dx = 0, int dy = 0) { *this = p; x += dx; y += dy;}
   //this structure takes 2 values of x and y and initialises
   //x and y of current Pos object with those values
   Pos(int _x, int _y) { x = _x; y = _y; }
   //this is overloaded operator < which returns true if value of current x is <
   //value of x in given Pos or if x are equal then checks y
   bool operator<(const Pos & p) const { return (x < p.x) || (x == p.x && y < p.y); }
   //this is overloaded == operator which returns true if both x and y values of
   //current and given Pos in arguments are equal
   bool operator==(const Pos & p) const { return x == p.x && y == p.y; }
   //this is default constructor which initialises x and y with -1
   Pos() {x = -1; y = -1;}
};
//demonstrating above struct
int main()
{
   //initialises first with x=2 and y=3
   Pos first(2, 3);
   //this line initialises second = first, then
   //increement x of second with 1 and y with also 1
   Pos second(first, 1, 1);
   //printing first Pos
   cout << "Position of first Pos: \nx: " << first.x << "\ny: " << first.y << endl;
   //printinf second Pos
   cout << "Position of second Pos: \nx: " << second.x << "\ny: " << second.y << endl;
   string isEaual = first == second ? "Yes\n" : "No\n";
   //printing if first is equal to second
   cout << "Is first equal to second? " << isEaual;
   string isless = first < second ? "Yes\n" : "No\n";
   //printing if first is equal to second
   cout << "Is first less than second? " << isless;
}

Output:

Position of first Pos: X: 2 y: 3 Position of second Pos: X: 3 y: 4 Is first equal to second? No Is first less than second? Yes