View source for Add without plus

== Interview Question : Add without using operator + ==
The task here is to write a function that adds two numbers without using the operator + or any other arithmetic operator.
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'''''Approach:''''' What choice do we have if we cant use operators? Bits!! 
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1) XOR the two numbers - This gives their sum without any carry.
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2) AND the numbers and left shift to do a carry without any further addition.
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3) Recurse until there is nothing left to carry.
<syntaxhighlight lang="C">
int addNoOperator (int x, int y)
{
	if (y==0) return x;  // Base case
	int add = x ^ y; // add without any carry
	int carry = (x & y) << 1; // carry, but no addition
	return addNoOperator (add, carry); // recurse with add + carry
}
</syntaxhighlight>