Try to convert stack to string but output received is special characters

Question

I do an exercise on Hackerrank:

Task
Given a base-10 integer, n, convert it to binary (base-2). Then find and print the base-10 integer denoting the maximum number of consecutive 1's in n's binary representation. When working with different bases, it is common to show the base as a subscript.

Example

The binary representation of 125 is 1111101. In base 2, there are 5 and 1 consecutive ones in two groups. Print the maximum, 5.

My solution is: I create a stack, push binary converted to it, and then I put it into new string. But when I run in dev-C++, the output I receive is just special characters. Can you explain to me and let me know how to fix?

#include <bits/stdc++.h>

using namespace std;

int main()
{
    int n;
    cin >> n;
    cin.ignore(numeric_limits<streamsize>::max(), '\n');
    stack<char>st;
    int temp;
    while(n!=0){
        temp = n%2;
        n=n/2;
        st.push(temp);
    }
        string s;

while(st.empty() == false){
    s = s + st.top();
    st.pop();
    }
cout << s;    // I try input n=5 but output is :) :)

// Count the maximum number of consecutive 1's
    int d=0;
    int max=0;
    for (int i=0; i<s.size(); i++){
        if (s[i]=='1') d++;
        if (s[i]=='0'){
            if (d>max) {
                max=d;
                d=0;
            }
            else d=0;
        }
    }
    cout << max;
    return 0;
}