How to get the length of an array?

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In C++ you can get the length of an array by calculating it:

int sz = sizeof(arr) / sizeof(arr[0]);

This takes the memory, used for your array and divides it by the size of the elements inside.
However there’s also another better(sometimes) solution. All you need to do is to create a template function:

template<typename T, size_t N>
int length(const T (&)[N])
{
    return N;
}

Here’s how to use this:

int main()
{
    int arr1[] = {1,2,3,4,5,6,7};
    double arr2[] = {1.1,2.2};
    char *arr3[] = {"el", "em", "en", "ts"};
    
    printf
    (
        "arr 1: %d\narr 2: %d\narr 3: %d\n",
        length(arr1),
        length(arr2),
        length(arr3)
    );
    
    system("pause");
    return 0;
}

Technologies Ignited