How to find greatest of 3 numbers?

CODE

How to find greatest of 3 numbers?

//Write a program to find greatest of 3 numbers…..

#include<iostream>

using namespace std;

class gr

{

    int a,b,c,max;

    public:

    void input()

    {

        cout<<"\n enter a,b,c:";

        cin>>a>>b>>c;

    }

    void pro()

    {

        if(a>b)

        {

            if(a>c)

                max=a;

            else

                max=c;

        }

        else

            if(b>c)

                max=b;

            else

                max=c;

    }

    void out()

    {

        cout<<"\n greatest number="<<max;

    }

};

int main()

{

    gr obj;

    obj.input();

    obj.pro();

    obj.out();

}

Output:

enter a,b,c:45

78

26

 greatest number=78