C++ array – expression must have a constant value

arraysc

I get an error when I try to create an array from the variables I declared. 

int row = 8;
int col= 8;
int [row][col];

Why do I get this error:

expression must have a constant value.

Best Answer

When creating an array like that, its size must be constant. If you want a dynamically sized array, you need to allocate memory for it on the heap and you'll also need to free it with delete when you're done:

//allocate the array
int** arr = new int*[row];
for(int i = 0; i < row; i++)
    arr[i] = new int[col];

// use the array

//deallocate the array
for(int i = 0; i < row; i++)
    delete[] arr[i];
delete[] arr;

If you want a fixed size, then they must be declared const:

const int row = 8;
const int col = 8;
int arr[row][col];

Also, 

int [row][col];

doesn't even provide a variable name.

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