Problem with variable

Hi,

Im fairly new with programming. Im following up my last class on programming with c++.

The question i have is very simple.

Lets say you want to create 10 different variables and give them name hello1 hello2 etc...

I want to use for(). But the problem I have is that i can't understand how you can use a variable for defining a variables name.

example:

Code:

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#include <iostream>
using namespace std;

int main (){

int i;


for(i = 0; i<10; i++){

char hello(i);*
cin >> hello(i);**
cin.ingore(1000, '\n');
}

//this would give us the input for our hello0 and hello5 variable.
cout << endl << endl << hello0 << hello5;

return 0;
}

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*(this is where I want i to be, so that for() can create 10 different hello variables with the name hello0 hello1 hello2 etc...)

**(i.... same here, each time for() goes a lap i want the next variable to be used in the cin phrase)

You probably want to use an array. Read the tutorial on arrays.

I would not like to use an array. I just want to create 10 variables. by using a variable i for defining each variables name.

Quote:

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I would not like to use an array. I just want to create 10 variables. by using a variable i for defining each variables name.

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C++ does not have variable variables, so barring some unnecessary yet creative macro tricks (that I do not know of) this is not possible. Generally an array really is the correct solution when you are faced with such a problem.

I don't think what you want is possible, so the best you can do is stick with the array ^^

strange it seems like such an easy thing to implement. Well then i will just read more about arrays then :/

Quote:

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strange it seems like such an easy thing to implement.

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It is indeed an easy thing to implement... with arrays.

Quote:

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Originally Posted by AdampqmabA

strange it seems like such an easy thing to implement.

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If you think that, you don't understand the separation of compilation and execution yet.

Quote:

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Originally Posted by AdampqmabA

strange it seems like such an easy thing to implement. Well then i will just read more about arrays then :/

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It would be relatively easy to make dynamic variables in a language where variables are created at runtime (when the application runs). In C and C++, ALL variables are created at compile-time [there are ways around that, but that involves pointers (which is a sort of variable that holds a reference to a lump of memory that can in turn hold other things), which is a couple of steps away from where you are at the moment, I suspect], so the compiler needs to know what value i has to make the variable for you. Since that is impossible for the compiler to know in most situations (including this one, as i changes throughout the runtime of the application), it doesn't work like you expect.

The reason C and C++ are not createing variables at runtime has to do with the extra overhead that is involved with that. That is what makes C and C++ really fast to run. But it means some extra work at compile time and sometimes extra work for the programmer. You can't have it both ways, I'm afraid.

Laserlight, I don't think macros would work. Templates perhaps, but even that would probably be streatching it in this case.

--
Mats

Quote:

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Originally Posted by matsp

Laserlight, I don't think macros would work.

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Neither do I, but my lack of knowledge of the more creative aspects of the preprocessor is enough for me to give it the benefit of the doubt.

Quote:

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Originally Posted by matsp

Templates perhaps, but even that would probably be streatching it in this case.

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Templates won't cut it, or we can claim that arrays are variable variables.

Actually, macros would work. The code would be completely unreadable.