# Switch Sign of a Number

In this lesson, we make use of the NOT operator to switch the sign of a number.

## We'll cover the following

## Introduction

In this question, we take input and switch its sign.

## Problem Statement

We need to write a program to switch the sign of a number.

```
Input: 10
Output: -10
```

## Solution

We already know that 2’s complement of any number gives a negative number with the formula below.

**Formula**

~x = ($2^{32}$ - x)

For example,

```
>if, x = 1
~x = -2
if, y = 10
~y = -11
```

So if you see the pattern, the number is negated and converted to 2’s complement.

```
number = 8
~number = -9
----------------------------
~number + 1 = (-9 + 1) = -8
----------------------------
```

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