tutorial 4 section B yeo rev.

//http://pastebin.com/u/TheWhiteFang#_=_
//yeo punya
//Tutorial 4 section b dectobin
#include <iostream>
#include <string>
using namespace std;

string DecToBin(int);
string OnesComp(string);
string AddBin(string, string);


int _tmain(int argc, _TCHAR* argv[])
{
    int input;
    cout << "Enter a number: ";
    cin >> input;
    string out = DecToBin (input);
    cout << out << endl;
    string out1comp = OnesComp(out);
    cout << out1comp << endl;
    string add = AddBin(out, out1comp);
    cout << add << endl;
    return 0;
}

string DecToBin(int dec)
{
    int remain=0;
    if(dec == 0)
        return "0";
    if(dec == 1)
        return "1";
    if (dec%2 == 0)
        return DecToBin (dec/2) + "0";
    else
        return DecToBin (dec/2) + "1";
}
string OnesComp(string bin){
    int len = bin.length();
    string temp;
    for (int i = 0; i < len; i++){
        if (bin[i] == '1')
            temp = temp + "0";
        else
            temp = temp + "1";
    }
    return temp;
}
string AddBin(string a, string b){
    string temp;
    if (a.length() == b.length()){
        for (int i = a.length()-1; i >= 0; i--){
            int tem = a[i] + b[i];
            if (tem > 97){
                temp[i] = '0';
                temp[i--] = '1';
            }
            else if (tem == 97)
                temp[i] = '1';
            else
                temp[i] = '0';
        }


    }
    return temp;
}