binary combination.

Hello,

I was working on a problem for generating the binary combination of x digits, as input. E.g. for x = 2, I have 2^2-1:

0--> 00
1--> 01
2--> 10
3--> 11

My program solves this by converting the decimal values to binary and then padding the required leftmost zeros.

Is there any other optimized solution?

You can show us your code and we will tell you if it can be made in other better way