TEX Quotes UVa Problem 272, Wrong answer and Correct Answer

I am referring to this https://onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=208 problem. The problem is easy and self-explanatory. I made 2 attempts out of which one was Accepted and other was given Wrong Answer verdict.

The code which got selected is below where I did char by char input and output,

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

int main() {
    char c;
    int flag = 0;
    while((c = getchar())!=EOF) {
        if(c == '\"') {
            if(flag) {
                cout<<'\''<<'\'';
                flag = 0;
            }
            else {
                cout<<'`'<<'`';
                flag = 1;
            }
        }
        else {
            cout<<c;
        }
    }
    return 0;
}

Whereas as following is the code which got wrong answer, here I took a line as input at a time. To me it does the same thing, but wrong answer.

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

int main() {
    string s;
    int flag = 0, c = 0;
    while(getline(cin, s)) {

        if(c) {cout<<'\n';}     //don't print newline first time
        c=1;

        for(auto& x : s) {
            if(x == '\"') {
                if(flag) {
                    cout<<'\''<<'\'';
                    flag = 0;
                }
                else {
                    cout<<'`'<<'`';
                    flag = 1;
                }
            }
            else {
                cout<<x;
            }
        }
    }
    return 0;
}

I am not able to figure out what's the issue ? It will be helpful if someone can point out the problem in the second version.