All permutations of strings(Recursive)

#include <iostream>
#include<cstring>
using namespace std;
void allpermutations(string s,string ans){
    if(s[0]=='\0'){
        cout<<ans<<endl;
        return;
    }
    
    for(int i=0;i<s.length();i++){
        char c=s[i];
    string ros=s.substr(0,i)+s.substr(i+1);
    allpermutations(ros,c+ans);
    }
    return;
}

int main()
{
    string s;
    cin>>s;
    string ans="";
    allpermutations(s,ans);
    return 0;
}