What's wrong?

Question

https://code.sololearn.com/c22s0zT1pfz4/?ref=app

Answer 1

I have made some changes in your code and now it is working properly :
#include <iostream>
#include <string>
using namespace std;

int k;
class myClass {
public :
int x,y,z;
int sum(){
cout<<"first number";
cin>>x;
cout<<"second number";
cin>>y;
cout<<"third number";
cin>>z;
k=x+y+z;
return k;
}
};
int main()
{
myClass ObjSum;
ObjSum.sum();
cout<<k;
}

Answer 2

uhm....
I just moved the cout thing to Main() :

class myClass {
int x,y,z,k;

int sum() {
cin>>x;
cin>>y;
cin>>z;
k=x*y*z;
return k;
}
};

int main() {
myClass ObjSum;
int OOP = ObjSum.sum();
cout<<OOP;
}

avoid publicly declare variable
(because public declare seems not OOP)

Answer 3

what makes class an Object Oriented is mostly because declaration is commonly private , not public ,
when you enter university , your Lecturer will teach those later on.

there's even Get and Set function , in your case :

int GetX(){ return x; }
int GetY(){ return y; }
int GetZ(){ return z; }
int GetK(){ return k; }

void SetX( int v ){ x=v; }
void SetY( int v ){ y=v; }
void SetZ( int v ){ z=v; }
void SetK( int v ){ k=v; }

inside that myClass

ask any University Lecturer , I dare you.
>:)

Answer 4

OK thanks, I see :d