Cracking The Coding Interview 1.5

//原文：
//
//	Write a method to replace all spaces in a string with ‘%20’.
//
#include <iostream>
using namespace std;
char* replace(char * str)
{
	if (str == NULL)
	{
		return NULL;
	}
	int size = strlen(str);
	char *tem = new char[size+1];
	int i = 0;
	int num = 0;
	while(str[i]!='\0')
	{
		if (str[i] == ' ')
		{
			num++;
		}
		tem[i] = str[i];
		i++;
	}
	tem[i] ='\0'; 

	char *s = new char[size + 1 + 2*num];
	int ii=0;
	int jj=0;
	while(tem[ii]!='\0')
	{
		if (tem[ii] != ' ')
		{
			s[jj] = tem[ii];
			ii++;
			jj++;
		}
		else
		{
			s[jj]='%';
			s[jj+1]='2';
			s[jj+2]='0';
			jj += 3;
			ii++;
		}
	}
	s[jj]='\0';
	return s;
}
int main()
{
	char s[] ="i am  chinese";
	cout<<replace(s)<<endl;
	return 0;
}