**Objective**: Given an array write an algorithm to print all the possible sub subsequences.

**Example:**

int [] a = {1, 2, 3}; Output: Possible sub sequences – {Empty}, {1}, {2}, {3}, {1, 2} ,{1,3}, {2, 3}, {1, 2, 3}

**Approach**:

- The approach will be similar to as discussed here Generate All Strings of n bits
- If we consider n= 3(same as the array size) then all possible combinations are [0, 0, 0] [1, 0, 0] [0, 1, 0] [1, 1, 0] [0, 0, 1] [1, 0, 1] [0, 1, 1] [1, 1, 1].
- So from the above combinations, wherever the bit is set to 1, place an array element at the position and wherever the bit is set to 0, ignore the array element.
- The above step will give the desired result.
- See the code below for better understanding.

**Time Complexity**: O(2^n)

**Complete Code:**

**Output:**

1 2 3 1 2 1 3 1 2 3 2 3 {Empty Set}