As we discussed in the previous video, the numbers are stored in their binary representation in computers and every single digit 0 / 1 is called bit.

Most languages allow you to perform operations which are bitwise ( this statement will make much more sense when we look at the operator themselves ). It is a fast, primitive action directly supported by the processor, and is used to manipulate values for comparisons and calculations.

*Syntax:*

`A & B`

*Values for bit combinations:*

```
a b a & b
------------------------
0 0 0
0 1 0
1 0 0
1 1 1
```

In other words, `a & b = 0`

unless `a = 1 and b = 1`

.

What does A & B mean:

A & B implies **a & b** for all corresponding bits of A and B.

So, lets say,

```
A = 21 ( 10101 ) and B = 6 ( 110 )
A & B =
1 0 1 0 1
& 0 0 1 1 0
------------------
0 0 1 0 0 = 4.
```

Syntax :

```
A | B
```

Values for bit combinations

```
a b a | b
------------------------
0 0 0
0 1 1
1 0 1
1 1 1
```

In other words, `a | b = 1`

unless `a = 0 and b = 0`

What does A | B mean :

`A | B`

implies

for all corresponding bits of A and B. So, lets say**a | b**

```
A = 21 ( 10101 ) and B = 6 ( 110 )
A | B =
1 0 1 0 1
| 0 0 1 1 0
------------------
1 0 1 1 1 = 23.
```

Syntax :

```
A ^ B
```

Values for bit a, b :

```
a b a ^ b
------------------------
0 0 0
0 1 1
1 0 1
1 1 0
```

In other words, `a ^ b = 1`

when **a and b are different**.

What does A ^ B mean :

A ^ B implies a ^ b for all corresponding bits of A and B. So, lets say

```
A = 21 ( 10101 ) and B = 6 ( 110 )
A ^ B =
1 0 1 0 1
^ 0 0 1 1 0
------------------
1 0 0 1 1 = 19.
```

Syntax :

`~A`

Values for bit a :

```
a | ~a
-------|-------
0 | 1
1 | 0
```

It's the **inverse of the bit**.

What does ~A mean

~A implies inverting every single bit in A. So, lets say

A = 21 ( 10101 ) and A is a char ( 1 byte )

~A =

0 0 0 1 0 1 0 1

--------------------------

1 1 1 0 1 0 1 0 = -22 ( Sign bit is 1 ).

Syntax :

`A >> x`

What does A » x mean :

`A >> x`

implies shifting the bits of A to the right by x positions. The last x bits are lost this way.

**Example :** Lets say

```
A = 29 ( 11101 ) and x = 2,
so A >> 2 means
0 0 1 1 1 0 1 >> 2
==== -> is lost
========== -----> this sequence of digit shifts to the right by 2 positions
----------------
0 0 0 0 1 1 1 = 7
```

A >> xis equal to division by pow(2, x). Think why.

Syntax :

`A << x`

What does A « x mean :

`A << x`

implies shifting the bits of A to the left by x positions. The first x bits are lost this way. The last x bits have 0. **Example** : lets say

```
A = 29 ( 11101 ) and x = 2,
so A << 2 means
0 0 1 1 1 0 1 << 2
============= ------> this sequence of digit shifts to the left by 2 positions
----------------
1 1 1 0 1 0 0 = 116
```

**A << x**** is equal to multiplication by pow(2, x).** Think why. *1 << x** is equal to pow(2, x).*