C++: Fastest method to check if all array elements are equal

Question

What is the fastest method to check if all elements of an array(preferable integer array) are equal. Till now I have been using the following code:

bool chec         


        

Answer 1

Once you have found a mismatching element you can break out of the loop:

bool check(const int array[], int n)
{   
    for (int i = 0; i < n - 1; i++)      
    {         
        if (array[i] != array[i + 1])
            return true;
    }
    return false;
}

If this is performance-critical then it can be further optimised slightly as:

bool check(const int array[], int n)
{   
    const int a0 = array[0];

    for (int i = 1; i < n; i++)      
    {         
        if (array[i] != a0)
            return true;
    }
    return false;
}