VS 2010 treating code differently to Dev C++

[Chazzmundo]

Hi there, I recently made a program using Dev C++ and it would compile and run just as I wanted it. I then imported the .cpp files into Visual Studio 2010 Ultimate and went to recompile except it is not compiling the following part of a function. The code in question is:

string Descrambler::order(string word) //descramble words and check them
{
      string input = word;
      int len = word.length(); //length of string
      
      int num[len]; //how many chars there are
...

This would be fine in Dev C++. However in VS it gives the following error:

	1	IntelliSense: expression must have a constant value	

This seems odd and I am unsure of what I am doing wrong. I changed it to the following but it still gave the same error:

string input = word;
int len = 2; //length of string
int num[len];

I see no reason in why this would work fine in Dev C++ but not in VS. any help would be greatly appreciated thank you.

[firedraco]

That is because

int len = 2; //length of string
int num[len];

is illegal in standard C++.

You must use dynamic allocation to do this:
http://cplusplus.com/doc/tutorial/dynamic/

Btw, Dev C++ is old and outdated, I hope that's why you are trying something else.

[z05DSL3A]

Dev-C++ got it wrong, C++ standard only allows for constant integer values to be used for arrays.

[filipe]

int len = 2; //length of string
int num[len];

This isn't legal C++. In C++, a stack allocated array must have a constant as its size. And you shouldn't use Dev-C++ because it hasn't been updated in over 5 years.

EDIT: :)

[Chazzmundo]

Cheers guys. Ok this is just annoying. I prefer the Dev approach it is much more flexible XD

But yes the only reason I used Dev in the first place was that I was unable to download VS to my home comp (vista :'( ...).

[hanst99]

The devc++ isn't more flexible, you can do the same things in standard c++. You just do it a bit differently. In C++ you can just use vectors, or dynamic allocation as already pointed out.

New throws an exception when the memory allocation fails, alone because of that it's better.