C++ "dynamic" arrays

Question

I've got some problems/misunderstandings with arrays in C++.

int myArray[30]; myArray[1]=2; myArray[2]=4;

This is spitting out a lot of compiler errors. I don't think it is necessary to include them here as this is an easy question for everybody with experience in C(++) I guess

Why doesn't this work?
Is there a way to create a "dynamic" array that has a fixed ammount of values (so no malloc needed) but where I can change the values during runtime?

This should work just fine (in the right context). What are the errors? — Tom Smith
– Tom Smith, Commented Feb 11, 2010 at 23:41
When you ask a question about a code that produces a compiler error, it is always a good idea to include the compiler error, even though it might be an easy task. If not for clarity of the problem, then for helping others attempting to find the answer to the problem later on. Besides in programming when only showing small snippets of code, it can very well be that the error is outside the shown code. — Tommy Andersen
– Tommy Andersen, Commented Feb 11, 2010 at 23:41
This will not spew any compiler errors, unless there's something wrong with the context. Any you are not sayng anything about the context. — AnT stands with Russia
– AnT stands with Russia, Commented Feb 11, 2010 at 23:44
give us either a complete code that produces the error, or the error itself ... both of them it's even better :) — f4.
– f4., Commented Feb 11, 2010 at 23:45

R Samuel Klatchko · Accepted Answer · 2010-02-11 23:41:39Z

I'm guessing you have that outside of a function.

You are allowed to define variables outside of a function. You can even call arbitrary code outside of a function provided it is part of a variable definition.

// legal outside of a function int myArray[30]; int x = arbitrary_code(); void foo() { }

But you cannot have arbitrary statements or expressions outside of a function.

// ILLEGAL outside a function myArray[1] = 5; void foo() { // But legal inside a function myArray[2] = 10; }

anon · Accepted Answer · 2010-02-11 23:42:36Z

Are you saying that this doesn't compile:

int main() { int myArray[30]; myArray[1]=2; myArray[2]=4; }

If it doesn't, you have something wrong with your compiler setup. As I said in my comment, we need to see the error messages.

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