segmentation fault in c++ using recursion

Question

I was solving the problem to find all possible substrings of a string using recursion but I was getting segmentation fault.

#include<iostream>
using namespace std;

void subset(string s,string output){
    if(s.length()==0){
        cout<<output<<" ";
        return ;
    }
   
    string op1=output;
    string op2=output;
    op2.push_back(s[0]);
    s.erase(s.begin()+0);
    subset(op1,output);
    subset(op2, output);
    return;
    
}

int main(){
    subset("ab","");

    return 0;
}

question from:https://stackoverflow.com/questions/65856831/segmentation-fault-in-c-using-recursion

Answer 1

You sending wrong string in recursive call does this work

  #include<iostream>
using namespace std;

void dubset(string s,string output){
    if(s.length()==0){
        cout<<output<<" ";
        return ;
    }
   
    string op1=output;
    string op2=output;
    op2.push_back(s[0]);
    s.erase(s.begin()+0);
    dubset(s,op1);
    dubset(s, op2);
    return;
    
}

int main(){
    dubset("ab","");

    return 0;
}