C++ Tutorials - Absolute n00b spoonfeed

Doctor salt, I think you're getting a bit confused. You are partly right, in that everywhere you go, you would be able to access those variables inside the class but to be able to access them, you need an object (unless they are static) and the object is subject to the rules of scope.

Despite this, you shouldn't be worrying about scope, because it's a good thing. Without scope, we might accidentally change something and not realise it, because the compiler sees it as a valid statement and it will run at runtime.

Although scope has its limitations, you can sort of bypass these with references and pointers. I'll say no more.

Yeah... I think he gets it, it's just confusing to talk about.

I replaced the above lines, to beneath where the program decleared the char: "letter"

Correct me if i'm wrong but it works fine for me:

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#include <iostream>
using namespace std;


void prinTLetteRGiven();

int main()
{
   char letter;

   cout << "Please input 1 letter: ";
   cin >> letter;
     
   cout << "The letter you typed in was " << letter << endl;


   char end;
   cin >> end;
   return 0;
}

the reason it only has one include is that i'm using another compiler named: dev-C++

Oh hai guys!

Here is the code:

Code: Select all



    #include "stdafx.h"
    #include <iostream>
    using namespace std;


    void prinTLetteRGiven()
    {
       cout << "The letter you typed in was " << letter << endl;
    }


    int main()
    {
       char letter;

       cout << "Please input 1 letter: ";
       cin >> letter;
       prinTLetteRGiven();

       char end;
       cin >> end;
       return 0;
    }



(Ok so for this one there are many possible ways of coding this. I believe that this is the best... )

In case you didn't see the line is on error 7 and 8, oh wait I meant the error is on line 7 and 8. Lol.

Code: Select all

    void prinTLetteRGiven()
    {
       cout << "The letter you typed in was " << letter << endl;
    }


Oh noes! What do we do Argio?????????????? Halp!

Well, this is what I think is the best way to do this. This also may optomize the program to its fullist extent. Isn't that what we wanted?

Code: Select all


    #include "stdafx.h"
    #include <iostream>
    using namespace std;


    void prinTLetteRGiven(char letter)
    {
       cout << "The letter you typed in was " << letter << endl;
    }


    int main()
    {
       char letter;

       cout << "Please input 1 letter: ";
       cin >> letter;
       prinTLetteRGiven(letter);

       char end;
       cin >> end;
       return 0;
    }


What the hell Argio how does this work???

Well, its is very simple.
Lets think of this as real life objects...
A MacOSX computer = letter

So I want to print out the character that is MacOSX right?
Ok but here is the problem the compiler hasn't told the program what letter is. So essentially the computer has no idea what type it is, what it could contain, or if its anything really. So now because we havn't told the program what lMacOSX is or anything about it, it could be a cake, it could be a pie, it could be the worst operating system in the universe, it could contain the value of 7, or any value for that matter. So if I want to print this out what is going to happen????

Well, this starts something called Undefined Behavior. And this could result in major glitches within your program or even in some cases operating system crashes.

This is what I did to fix it:


I made it so that letter is defined as a incoming chat from the function calling the prinTLettRGiven function. So when I called it in the main function I had to tell it to bring along a variable in this case the main function's letter variable. Thus when the prinTLettRGiven function gets called it brings along letter and then tells it to output letter !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


YAY

This was yet another good and easy Project.
The error was due to the code below.

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char letter;

There was noting wrong with how it was written, but the problem was that code was out of visible range. It was not in the same scope so the "void prinTLetteRGiven()" couldn't see it, basically you had to move it to a more see able spot, a place where all functions can easily see it. I don't know if I said it correctly




Here is how the code should be.

Code: Select all

#include "stdafx.h"
#include <iostream>
using namespace std;

char letter;
void prinTLetteRGiven()
{
   cout << "The letter you typed in was " << letter << endl;
}


int main()
{
   cout << "Please input 1 letter: ";
   cin >> letter;
   prinTLetteRGiven();

   char end;
   cin >> end;
   return 0;
}



Basically I moved it right below the "using namespace std;" making it visible to all the functions.
Btw, I am not cheating I maybe new, but I am doing it all on my own. Even though its just basic stuff.

@Symbol: Actually though your solution works, it is not the way to go...

What you've done is created a "Global Variable" which means that "char letter" belongs to public/general scope, not limited to any other scope. This means everyone everywhere can access and modify it, which is a bad thing to allow in your program. Variables should be limited to the scope where they'r needed.

Can you come up with a better solution which doesn't make a global variable?

Okay I see what your saying.

What if I replace

Code: Select all

void prinTLetteRGiven()
{
   cout << "The letter you typed in was " << letter << endl;
}

with

Code: Select all

void prinTLetteRGiven(char letter)
{
   cout << "The letter you typed in was " << letter << endl;
}

It seems to also work.
No more global scopes for me I guess.

Excellent! There ya go