So I was debugging this code and managed input/outputs in separate files. I ran the same code with same flags in codeblocks and WSL ubuntu 18.04, they gave me two different outputs.

#include<bits/stdc++.h>

using namespace std;

int main() {
    #ifdef ROBIN
        freopen("in", "r", stdin);
        freopen("out", "w", stdout);
    #endif // ROBIN
    int t, d = 0;
    cin >> t;
    getchar();
    // getchar();
    while(t--) {
        d++;
        string ss, tt;
        // getchar();
        getline(cin, ss);
        // getchar();
        getline(cin, tt);
        string sss = "", ttt = "";
        cout << "SS: " << ss << endl;
        cout << "TT: " << tt << endl;
        for(int i = 0; i < ss.size(); i++) {
            ss[i] = tolower(ss[i]);
            if(ss[i] != ' ') {
                sss += ss[i];
            }
        }
        for(int i = 0; i < tt.size(); i++) {
            tt[i] = tolower(tt[i]);
            if(tt[i] != ' ') {
                ttt += tt[i];
            }
        }
        sort (sss.begin(), sss.end());
        sort (ttt.begin(), ttt.end());
         if(sss == ttt) {
    cout << "Case " << d << ": " << "Yes" << endl;
        }
        else {
        cout << "Case " << d << ": " << "No" << endl;

        }
    }
return 0;
}

Input

3
Tom Marvolo Riddle
I am Lord Voldemort
I am not Harry Potter
Hi Pretty Roar to man
Harry and Voldemort
Tom and Jerry and Harry

Output (Code::Blocks)

SS: Tom Marvolo Riddle
TT: I am Lord Voldemort
Case 1: Yes
SS: I am not Harry Potter
TT: Hi Pretty Roar to man
Case 2: Yes
SS: Harry and Voldemort
TT: Tom and Jerry and Harry
Case 3: No

Output (WSL)

SS:
TT: Tom Marvolo Riddle
Case 1: No
SS: I am Lord Voldemort
TT: I am not Harry Potter
Case 2: No
SS: Hi Pretty Roar to man
TT: Harry and Voldemort
Case 3: No

I included sample input-output in the code. I would appreciate it if someone gives me a proper explanation of this. Thanks.
Flags:
-DROBIN
-std=c++14
-O2