how to get all possible combination (programmatically)

[benmartin101]

I'm trying to figure out how to write a code that would allow me to get all the possible combination. In this case, I have 4 fruits: apple, orange, grape, mango. I want to know all the possible combination, for example:

apple (a possible combination)
apple,orange (another possible combination)
apple,grape (another possible combination)
apple,orange,grape (another possible combination)
and so on...

[passel]

I'm assuming order doesn't matter, that is whether (apple, orange), or (orange,apple) they are the same combination.
In which case, the way I would solve it, ironically, is to maintain a strict order, as you have by keeping apple first in your example combinations.
So, treat each fruit like a number from 1 to 4, and generate combinations, where the numbers always have to be in numerical order, and you'll have all your combinations.
1
2
3
4
12
13
14
123
124
1234

See if you can figure a way to loop 4 times when you have 1 item, 3 times when you have 2 items, 2 times when you have 3 items, and 1 time when you have 4 items.

See a pattern?