劍指offer 替換空格 c++

#include<iostream>
#include<stdio.h>
using namespace std;

class Solution
{
	public:
			void Repalce_Space(char *str ,int length)
			{
		
				int space_count = 0;
				int o_length = 0;
				int n_length;
				int i = 0;
				
				while(str[i] != '\0')
				{
					o_length++;
					if(str[i] ==' ')
					{
						space_count++;
					}
				    i++;
				}
				n_length = o_length + 2*space_count;

				char *p1 = str + o_length;
				char *p2 = str + n_length;
    	
				while(p1 != p2)
				{
					if(*p1 ==' ')
					{
						*p2--='0';
						*p2--='2';	
						*p2--='%';		
					}
					else
					{
						*p2-- = *p1;
					}
					--p1;
				}
			
			}
};

int main()
{	Solution solution;
	int length = 1024;
	int i=0;
	char str[length] = {"We Are Happy"};//不能直接用字符串給數組賦值，得加大括號。
	solution.Repalce_Space(str ,length);
	while(str[i]!='\0')
	{
		printf("%c",str[i]);
		i++;
	}
	return 0;
}