Array Problem

Im Trying to initialize this array and when I do this:

code:
void merge(int A[], int p, int q, int r)
{
int B[r-p+1];
/code

It doesnt work, i get an error because the compiler doesnt know what r and p are.

I think what you are trying to do would only work with a C99 compliant compiler. You need to allocate memory for the array dynamically.

Code:

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int * B = new int[r-p+1];

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You should ensure r-p+1 is positive and you will also need to remember to delete the memory once you are done with the array.

An array's dimension has to be a constant integer. Those are the rules. So, you can't have variables listed for an array's dimension, e.g. you can't do this:

Code:

---

int x;
cout<<"enter an array size: ";
cin>>x;
int myArr[x];

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Nor can you do what you are trying.

If you need to use a variable for an array's dimension, then you have to know what pointers are and you have to know how to dynamically allocate memory, e.g.

Code:

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int x;
cout<<"enter an array size: ";
cin>>x;
int* p = new int[x];

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You also have to delete any memory that you dynamically allocate with new after you are done with it. In this case, that would take the form:

Code:

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delete[] p;

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