Array Example

Destruction and Deallocation for Arrays of Primitives

Destruction and deallocation both happen for arrays of primitives the same way that the happen for individual primitives:

• At the closing } of the declaring block, the variable is destroyed. Nothing happens to the values (because they're primitives) but the name of the array is no longer valid to use.
• At the closing } of the function, all of the memory for the variable is deallocated.

Let's Try an Example!

int multiplyByThreeTheHardWay(int multiplier)
{
    constexpr size_t MULTIPLICAND = 3;
    int scratchSpace[MULTIPLICAND];

    for (size_t i=0; i<MULTIPLICAND; ++i) {
        scratchSpace[i]=multiplier;
    }

    int product=0;

    for (size_t i=0; i<MULTIPLICAND; ++i) {
        product += scratchSpace[i];
    }

    return product;
}

int main()
{
    int magicNumber = multiplyByThreeTheHardWay(14);
    cout << magicNumber << endl;
    return 0;
}

See if you can walk through this code and draw the memory diagram!

New memory diagram rule:

• When a variable is declared constexpr, draw a padlock next to its name in the diagram.
• The padlock indicates that you can't use this name to change the value at this spot.

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