Editing Integer square root (section)

===Linear search using addition===
In the program above (linear search, ascending) one can replace multiplication by addition, using the equivalence
<math display="block">(L+1)^2 = L^2 + 2L + 1 = L^2 + 1 + \sum_{i=1}^L 2.</math>

<syntaxhighlight lang="c" line="1">
// Integer square root
// (linear search, ascending) using addition
unsigned int isqrt(unsigned int y)
{
	unsigned int L = 0;
	unsigned int a = 1;
	unsigned int d = 3;

	while (a <= y)
	{
		a = a + d;	// (a + 1) ^ 2
		d = d + 2;
		L = L + 1;
	}

	return L;
}
</syntaxhighlight>