Interview Question for Software Development Engineer In Test (SDET) at Microsoft:

The only algorithm I know (from math) for verifying this is that the sum of each two should be bigger than the third, so it looks pretty straighforward to me, but:

bool can_form_triangle(int a, int b, int c)
{
    if (a + b <= c)
    {
        return false;
    }
    if (a + c <= b)
    {
        return false;
    }
    if (b + c <= a)
    {
        return false;
    }

    return true;
}