variale array lenght help

[dncp4312]

hello, i want to ask for a number as an input during runtime and then create an 2-dimensional array of size as specified by user. i.e. if the user inputs 3, the array should be of size 3X3, and likewise...

could any one please help ???

[Catfish666]

You can do this in C (more specifically C99, the C language standard of 1999).

#include <stddef.h>
#include <stdio.h>

// ...

size_t sz;

printf("Input size: ");
scanf("%zu", &sz);

int matrix[sz][sz];

// now we can use matrix[x][y] 

In C++, you cannot legally do the above, although certain compilers allow it (such as GCC).
The C++ way to do this is to use a vector of vectors.

#include <cstddef>
#include <iostream>
#include <vector>

// ...

std::size_t sz;

std::cout << "Input size: ";
std::cin >> sz;

std::vector<std::vector<int> > matrix(sz, std::vector<int>(sz));

// now we can use matrix[x][y] 

Edit: C example mistakes.

[dncp4312]

Btw, i use c++, standard one(the one with the blue editing screen).

And i dont have a vector header file. . .
Neither cstdef. . .

[MikeyBoy]

<vector> and <cstddef> are parts of the standard library, which means they are part of C++.

If you don't have them, then you don't have a proper C++ implementation.

I have no idea what you mean by "c++, standard one(the one with the blue editing screen)". C++ is a language, not a IDE or an editing tool.

[Catfish666]

@ dncp4312: what tools do you use?

If you use Pelles C IDE, be advised that it is for C only (C99 and C11) and does not support C++.

[dncp4312]

@catfish
I knw its compiler. . .
By editing screen, i meant the screen where you type the codes.
Here's what my compiler's about section displyays :
Turbo C++
Version 3.0
Copyright (c) 1990, 1992 by
Borland International, Inc.

I have version 4.5 too, but dont use it though. . .

One more thing, cud you please provide me with the download link of compiler you use. . .

[Catfish666]

Perhaps it is best that you upgrade to Visual Studio Express 2013 IDE:
http://www.visualstudio.com/en-us/downloads/download-visual-studio-vs#DownloadFamilies_2

If VS 2013 is too big and doesn't run well on your computer, try Orwell Dev-C++ IDE:
http://sourceforge.net/projects/orwelldevcpp/

Personally, I prefer using command line GCC and separate editor, instead of an IDE.
However if you're a beginner, this may be unpleasant, so you should use one of the above.
http://nuwen.net/mingw.html
http://www.sublimetext.com/

[dncp4312]

Thnx for help. . .
Nd i would like to knw, if you were able to recognize the compile i use. . .
Nd, yeah i am a beginner, currntly learning 2D arrays. . .

[Catfish666]

Thnx for help. . .
Nd i would like to knw, if you were able to recognize the compile i use. . .
Nd, yeah i am a beginner, currntly learning 2D arrays. . .

Friendly advice: write full words. Incomplete words may cause people to dislike you.

[dncp4312]

Okay, sorry, i am just habituated. . .
Thanks Anyways. . .