#include<iostream>
using namespace std;

class Solution {
public:
    void replaceSpace(char *str,int length) {
        if(str == NULL || length<=0)
            return;
        int length_origin = 0;
        int blank = 0;
        while(*str != ‘\0‘){
            if(*str == ‘ ‘){
                blank++;
                length_origin++;
                str++;
            }
            else{
                length_origin++;
                str++;
                continue;
            }
        }
        cout<<‘a‘<<endl;
        int length_new = length_origin+2*blank;
        cout<<‘a‘<<endl;
        if(length_new > length)
            return;
        else{cout<<‘b‘<<endl;
            char *str_new = str+2*blank;
            cout<<‘b‘<<endl;
            while(str_new != str){
                if(*str == ‘ ‘){
                    *str_new = ‘0‘;
                    *(str_new-1) = ‘2‘;
                    *(str_new-2) = ‘%‘;
                    str_new = str_new -3;
                    str--;
                }
                else{
                    *str_new =*str;
                    str_new--;
                    str--;
                }
            }
        }
    }
};
int main(){
    // cout<<‘a‘;
    char str[] = "we are happy";
    cout<<str<<endl;
    Solution replace;
    replace.replaceSpace(str,50);
    cout<<‘a‘;
    cout<<‘a‘<<endl;
    cout<<‘a‘<<endl;
    cout<<str<<endl;
    return 0;
}

we are happy
a
a
b
b
aa
a
we%20are%20happy