Can the same object initialize a private variable via a constructor more than once

[dtaqee88]

It'd be convenient to just update a private member variable whenever I
wanted without having to declare a new object every time. Is this possible?
Thanks for any response.

///Playing with inheritance and other stuff
#include <iostream>
#include <string>
#include <cctype>
#include <algorithm>
using namespace std;

class yeehaw
{
    private:
            int ketchup;

    protected:
            string kong;///* try to access this directly from child class *
            
    public:
            yeehaw()
            {
                ketchup = 0;
            }

            yeehaw(int a) : ketchup(a) {}   ///New notation

            void printKetchup() { cout<<ketchup<<endl; }
};

int main()
{
    yeehaw yoshi;

    cout<<"Before initializing ketchup to 25: ";
    yoshi.printKetchup();

    ///will not let me initialize constructor to a new value w/out declaring new object
    yeehaw mcdouble(25);

    cout<<"After initializing ketchup to 25: ";
    mcdouble.printKetchup();

    return 0;
}

[Athar]

Just add a setter...

[vlad from moscow]

Another way is to write an assignment operator. For example

yeehaw & operator =( int red )
{
   ketchup = red;
   return ( *this );
}

[dtaqee88]

Thanks. That's what I would do but just wanted to know if it was even possible. I've never heard of operator...will check it out.thanks again

[dtaqee88]

I just tried to play with but I don't get it Vlad. Is the yeehaw function you specified a constructor. How would I call it?..looking up operator now...

[vlad from moscow]

class yeehaw
{
    private:
            int ketchup;

    protected:
            string kong;///* try to access this directly from child class *
            
    public:
            yeehaw()
            {
                ketchup = 0;
            }

            yeehaw(int a) : ketchup(a) {}   ///New notation
            yeehaw & operator =( int red )
            {
                ketchup = red;
                return ( *this );
            }
            void printKetchup() { cout<<ketchup<<endl; }
};


int main()
{
    yeehaw yoshi;
    ...
    yoshi = 25;
    ....

[dtaqee88]

Wow thanks. What's the need for the "yeehaw & operator" function? The program compiled and reinitialized the private variable fine without it.

[vlad from moscow]

Well, show me how you do the statement

yoshi = 25;

without the operator?!

[Athar]

Since the constructor is non-explicit, this will compile even without operator=.
Without an appropriate operator=, when you write
yoshi = 25;
It's as if you had written:
yoshi = yeehaw(25);
In other words, you still create a new (temporary) object every time.

[dtaqee88]

You've misunderstood. I meant the public function in the yeehaw class:

            yeehaw & operator =( int red )
            {
                ketchup = red;
                return ( *this );
            }

The program compiled fine and yoshi was updated just fine without the function. I don't know how to do it without the equal operator you just showed me. I played around with that function and couldn't figure out for the life of me what it did...could you shed some light on it?

@Athar. That was my initial problem. After I declared an object from yeehaw: yeehaw yoshi(25), it wouldn't let me do it again

[vlad from moscow]

@Athar
Since the constructor is non-explicit, this will compile even without operator=.
Without an appropriate operator=, when you write

I did not take into account that there is a conversion constructor.:) I thought that there is only the default constructor.

[Athar]

You've misunderstood.

No, you did. I explained why it works without operator=(int).
The compiler provides an assignment operator that allows you to assign a yeehaw object to another yeehaw object automatically, in case you were not aware.

I don't know how to do it without the equal operator

It's the assignment (copy) operator, not equal operator.

Normally, to change a private member, you use a setter:
void setKetchup(int newKetchup) {ketchup=newKetchup;}

In order to avoid accidental conversions, you should make constructors with one parameter explicit:
explicit yeehaw(int a) : ketchup(a) {}

[dtaqee88]

sorry about the confusion


edit: @athar...Thanks. Honestly this concept is still murky.

I will use a setter like you said earlier but just to clarify....The only way I know how
to update a private member variable via a constructor is when you initially declare
an object and initialize a value:

yeehaw yoshi(42);

and how Vlad from moscow just showed me:

yoshi = 42;

So the equal operator does nothing? When I tried to update the private variable like
this:

yoshi(99);

it gave me an error.

[Athar]

A constructor initializes a new object. You cannot call it on an existing object.

So the equal operator does nothing?

It's still the assignment operator. And obviously it does do something.