[Solved] Complex C program [closed]

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Assuming your pool of characters is sorted and without repetitions (may need some preprocessing), generating the desired strings in lexicographic order is automatic (in the approach I have in mind).

Look at the short example of all nonempty strings that can be generated from “ABC” with the restrictions:

A
AB
ABC
AC
ACB
B
BA
BAC
BC
BCA
C
CA
CAB
CB
CBA

You need to keep track of

  1. How many characters you have chosen, which, and in which order: and int and a char[]
  2. How many characters you may still choose and which: an int and a bool[] (or char[], int[])

  3. How many strings you still need to output, since that will be modified in recursive calls: an int*

    void permute(char *pool, int pool_length, int num_picked, char *stringy,
    bool *picked, int max_length, int *strings_left) {

    int i;
for(i = 0; *string_left > 0 && i < pool_length; ++i) {
    if (pool[i] may be picked) {
        // 1. pick that as the num_picked + 1st character
        // 2. output and decrement *strings_left
        // 3. recur
        // 4. unpick pool[i]
    }
}

    }

I hope that helps and I haven’t given too much away.

solved Complex C program [closed]