LeetCode - 67. Add Binary

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
string addBinary(string a, string b)
{
    string c;
    int a_pos=a.length()-1,b_pos=b.length()-1;
    bool carry=0;
    while(a_pos>=0||b_pos>=0)
    {
        cout<<"\na_pos:"<<a_pos<<"b_pos"<<b_pos<<endl;
        char temp;
        if(a_pos<0)
        {
            temp=b[b_pos];
        }
        else if(b_pos<0)
        {
            temp=a[a_pos];
        }
        else
        {
            temp=a[a_pos]+b[b_pos]-'0';
        }
        temp+=carry;
        if(temp>='2')
        {
            carry=1;
            temp-=2;
        }
        else carry=0;
        cout<<"temp:"<<temp<<endl;
        c=temp+c;
        if(a_pos<=0&&b_pos<=0&&carry)
        {
            c="1"+c;
        }
        --a_pos;
        --b_pos;
        cout<<"c:"<<c<<endl;
    }
    return c;
}

string addBinary_2(string a, string b) {
    int carry = 0;
    int i = a.length() - 1;
    int j = b.length() - 1;
    string ans;
    while (i >= 0 || j >= 0) {
      int s = (i >= 0 ? a[i--] - '0' : 0) +
              (j >= 0 ? b[j--] - '0' : 0) +
              carry;
      carry = s >> 1;
      ans += '0' + (s & 1);
    }
    if (carry) ans += '1';
    reverse(ans.begin(),ans.end());
    return ans;
  }

int main()
{
    cout<<addBinary("11","1")<<endl;
    cout<<addBinary("1010","1011")<<endl;
    cout<<"addBinary_2\n";
    cout<<addBinary_2("11","1")<<endl;
    cout<<addBinary_2("1010","1011")<<endl;
    return 0;
}