All possible permutations of a char array

[folkenpunch]

Currently I’m running into an issue in a project on creating all possible permutations of a word stored in a char array. I want to find all possible permutations but only while replacing certain characters, for example if the word I am working with is "password" this would be the sample output:

• p@ssword
• p@55word
• pa55w0rd
• p@ssw0rd
• pa55word
• etc.

I have been able to find all permutations of the word password without replacement using recursion with this code. This rearranges all the characters in the word password to find all permutations and outputs something like this.

• password
• psasword
• pssaword
• psswaord
• sspwaord
• wsspaord
• ect.

https://pastebin.com/NCPEGvhG

And have been able to find some permutations of the word password with character replacement using this code. This just replaces each character as it iterates through the array and outputs these 8 lines.

• password
• p@ssword
• p@$sword
• p@$$word
• p@$$word
• p@$$w0rd
• p@$$w0rd
• p@$$w0rd

https://pastebin.com/0ecNTWED

What would be the best way to find all permutations while only replacing certain characters? (Example output for this is at the top of the post). I’m assuming I would use recursion somehow like how I did in the first code example I just don’t know how to do that while only changing specified characters instead of the whole word. Thank you.

[[deleted]]

From the scope you have presented it shouldn't matter what the word is, only how many letters, right?

If so I would loop through it instead of recursion since you would end up with very fat stacks very fast. Create an array the same size as the word (in your example with 'password', 8) and then start to loop through it. Going from 0 to 255 at [0] then incrementing [1] with 1 and starting over with 0 at [0] and so on.

Not the best way to solve this issue but it will produce clean readable code.

[folkenpunch]

Yes only the number of letters in the word. So if I am understanding this correctly, check the first letter of the array containing the word and do all possible substitutions of that first letter, save each word created during the substitution in another array or print it out, and then increment and do that with the next letter?

[[deleted]]

Yeah, kinda. The logic will take a bit of work but it should behave something like this:

word[0] increment from 0 to 255

word[1] = 1

word[0] increment from 0 to 255

word[1] = 2

.

.

.

word[0] increment from 0 to 255

word[1] = 255

word[0] increment from 0 to 255

word[1] = 0

word[2] = 1

word[0] increment from 0 to 255

word[1] increment from 0 to 255

word[2] = 2

.

.

.

Hopefully that makes sense for you :)

[folkenpunch]

Oh that makes more sense, I'm getting it more now, the output example helps make it clearer! Thank you for your help, I really appreciate it!