# Swift - Bitwise AND assignment operator

The Bitwise AND assignment operator (&=) assigns the first operand a value equal to the result of Bitwise AND operation of two operands.

(x &= y) is equivalent to (x = x & y)

The Bitwise AND operator (&) is a binary operator which takes two bit patterns of equal length and performs the logical AND operation on each pair of corresponding bits. It returns 1 if both bits at the same position are 1, else returns 0.

Bit_1 | Bit_2 | Bit_1 & Bit_2 |
---|---|---|

0 | 0 | 0 |

1 | 0 | 0 |

0 | 1 | 0 |

1 | 1 | 1 |

The example below describes how bitwise AND operator works:

50 & 25 returns 16 50 -> 110010 (In Binary) & 25 -> & 011001 (In Binary) ---- -------- 16 <- 010000 (In Binary)

The code of using Bitwise AND assignment operator (&=) is given below:

var x = 50 var y = 25 //Bitwise AND assignment operation x &= y //Displaying the result print("x = ", x)

The output of the above code will be:

x = 16

### Example: Check if a number is even or odd

The last bit of an even number is always *0*, whereas for an odd number it bit is always *1*. For a given number *n*, *(n & 1)* returns *0* if the *n* is even, else returns *1*.

Even Number: 50 -> 110010 (In Binary) & 1 -> & 000001 (In Binary) ---- -------- 0 <- 000000 Odd Number: 99 -> 1100011 (In Binary) & 1 -> & 0000001 (In Binary) ---- --------- 1 <- 0000001

The below code checks whether a given number is even or odd:

func CheckEven(_ myNum: Int) { var x = myNum x &= 1 if (x == 1) { print(myNum, " is an odd number.") } else { print(myNum, " is an even number.") } } CheckEven(50) CheckEven(99)

The above code will give the following output:

50 is an even number. 99 is an odd number.

❮ Swift - Operators