subsequences of string

/*
input : "abc" is a string
output : ["","a","b","c","ab","bc","ac","abc"]
          returing all the subsequences of input string.
*/          

#include<iostream>
using namespace std;

int subs(string input, string output[]){

    // base case
    if(input.empty()){      // .empty check for variable present or not
        output[0] = "";
        return 1;
    }

    string smallString = input.substr(1);

    // recursion
    int smallOutputSize = subs(smallString,output);

    // small calculation
    for(int i = 0; i < smallOutputSize; i++){
        output[i + smallOutputSize] = input[0] + output[i];
    }
    return 2*smallOutputSize;

}

int main(){

    string input;
    cin >> input;

    // dynamically made the o/p string
    string* output = new string[1000];

    // storing the o/p value no. to count variable
    int count = subs(input,output);
    
    // print the o/p array for count 
    for(int i =0; i < count; i++){
        cout << output[i] << endl;
    }
}