# LeetCode – Sum of Two Integers (Java)

Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.

Example:

Given a = 1 and b = 2, return 3.

**Java Solution**

Given two numbers a and b, a&b returns the number formed by '1' bits on a and b. When it is left shifted by 1 bit, it is the carry.

For example, given a=101 and b=111 (in binary), the a&b=101. a&b << 1 = 1010.

a^b is the number formed by different bits of a and b. a&b=10.

public int getSum(int a, int b) { while(b!=0){ int c = a&b; a=a^b; b=c<<1; } return a; } |

<pre><code> String foo = "bar"; </code></pre>