Program to format a number with thousands separator in C/C++

// C++ program to implement the
// above approach

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

// Function to put thousands
// separators in the given integer
string thousandSeparator(int n)
{
    string ans = "";

    // Convert the given integer
    // to equivalent string
    string num = to_string(n);

    // Initialise count
    int count = 0;

    // Traverse the string in reverse
    for (int i = num.size() - 1;
         i >= 0; i--) {
        count++;
        ans.push_back(num[i]);

        // If three characters
        // are traversed
        if (count == 3) {
            ans.push_back(',');
            count = 0;
        }
    }

    // Reverse the string to get
    // the desired output
    reverse(ans.begin(), ans.end());

    // If the given string is
    // less than 1000
    if (ans.size() % 4 == 0) {

        // Remove ','
        ans.erase(ans.begin());
    }

    return ans;
}

// Driver Code
int main()
{
    int N = 47634;
    string s = thousandSeparator(N);
    cout << s << endl;
}