Print all Subsequences of a string

C++ code
#include <iostream>
using namespace std;

int subs(string input, string output[]) {
	if (input.empty()) {
		output[0] = "";
		return 1;
	}

	string smallString = input.substr(1);
	int smallOutputSize = subs(smallString, output);
	for (int i = 0; i < smallOutputSize; i++) {
		output[i + smallOutputSize] = input[0] + output[i];
	}
	return 2 * smallOutputSize;
}

int main() {
	string input;
	cin >> input;
	string* output = new string[1000];
	int count = subs(input, output);
	for (int i = 0; i < count; i++) {
		cout << output[i] << endl;
	}
}


// or just printing the strings and not returning them
#include <iostream>
using namespace std;

void print_subs(string input, string output) {
	if (input.length() == 0) {
		cout << output << endl;
		return;
	}

	print_subs(input.substr(1), output);
	print_subs(input.substr(1), output + input[0]);
}

int main() {
	string input;
	cin >> input;
	string output = "";
	print_subs(input, output);
}

-----------------------------
Python 3.5

def subs(inp,output):# inp is the input string and output is the final output array
    
    # base case
    if(len(inp)==0):
        output[0]=""
        return 1
    
    smallString=inp[1:]
    smallOutput=subs(smallString,output)
    for i in range(smallOutput):
        output[i+smallOutput]=inp[0]+output[i]
    return 2*smallOutput
    
    
string=input().strip()
import math
sizeofoutput=math.pow(2,len(string))
output=[None]*int(sizeofoutput)
count=subs(string,output)
for i in range(count):
    print(output[i])   # the first one is the empty , so you cant see it