Error in Target-sum-subsets-official problem

Question

code-->
#include<iostream>
using namespace std;

void printTargetSumSubsets(int arr[], int idx, string set, int sos, int tar, int n)
{
if(sos > tar)
{
return ;
}

if(idx == n){
if(sos == tar)
{
cout<<set<<"."<<endl;
}
return ;
}

printTargetSumSubsets(arr, idx + 1, set + arr[idx] + ",", sos + arr[idx], tar,n);
printTargetSumSubsets(arr, idx + 1, set, sos, tar,n);
}

int main()
{
int n;cin>>n;
int arr[n];
for(int i = 0; i < n; i++)
{
cin>>arr[i];
}
int tar;cin>>tar;
printTargetSumSubsets(arr, 0,"", 0, tar, n);
}

output--->
main.cpp: In function bvoid printTargetSumSubsets(int*, int, std::string, int, int, int)b:
main.cpp:19:49: error: no match for boperator+b (operand types are bstd::stringb {aka bstd::__cxx11::basic_string<char>b} and bintb)
19 | printTargetSumSubsets(arr, idx + 1, set + arr[idx] + ",", sos + arr[idx], tar,n);
| ~~~ ^ ~~~~~~~~
| | |
| | int
| std::string {aka std::__cxx11::basic_string<char>}
In file included from /usr/local/gcc-9.2.0/include/c++/9.2.0/bits/stl_algobase.h:67,
from /usr/local/gcc-9.2.0/include/c++/9.2.0/bits/char_traits.h:39,
from /usr/local/gcc-9.2.0/include/c++/9.2.0/ios:40,
from /usr/local/gcc-9.2.0/include/c++/9.2.0/ostream:38,
from /usr/local/gcc-9.2.0/include/c++/9.2.0/iostream:39,
from main.cpp:1:
/usr/local/gcc-9.2.0/include/c++/9.2.0/bits/stl_iterator.h:423:5: note: candidate: btemplate<class _Iterator> std::reverse_iterator<_Iterator> std::operator+(typename std::rev

Answer 1

ravi kamble ,
It'll be easier to solve you problem if you tell what are you trying to do. What are expected results?

Answer 2

```
int n; cin>>n;
int arr[n];
```
this is not valid c++. It may compile on some compilers but it's not a standard way to make a dynamic sized array.

use new and delete instead to allocate memory dynamically .
or use std::vector
https://stackoverflow.com/questions/1887097/why-arent-variable-length-arrays-part-of-the-c-standard