ReplaceBlank

#include <iostream>
#include <string>
using namespace std;


void repalce(char str[], int length)
{
    int len = 0, blank = 0;
    if (length == 0)
        return;
    int i = 0;
    while (str[i] != '\0')
    {
        ++len;
        if (str[i] == ' ')
            blank++;
        ++i;
    }
    int fin_length = len + blank * 2;
    /*if (fin_length > length)
        return;*/
    while (len >= 0)
    {
        if (str[len] == ' ')
        {
            str[fin_length--] = '0';
            str[fin_length--] = '2';
            str[fin_length--] = '%';
        }
        else
        {
            str[fin_length--] = str[len];
        }
        len--;
    }
}

int main()
{
    string s1;

    while (getline(cin, s1))
    {
        int length = s1.length();
        char *str = new char[length * 2];
        strcpy(str, s1.c_str());
        repalce(str, length);
        cout << str << endl;
    }
    return 0;
}