Remove trailing and forward spaces

#include <bits/stdc++.h>
using namespace std;
#define ll long long

int main() {
    // your code goes here
    string str = " ah  na ";
    char space = ' ';

    size_t found = str.find(space);
    while(found!=string::npos){
        if(found==0 || found==str.length()-1){
            int pos =found;
            str.erase(pos, 1);
        }
        found = str.find(space, found+1);
    }

    cout<<str<<endl;
    return 0;
}