剑指offer-2.替换空格

class Solution {
public:
void replaceSpace(char *str,int length)
{
string s, sc = "%20";
for (int i = 0; i < length; i++)
{
if (str[i] == ' ') //如果是空格
{
s += sc;       //进行替换空格
}
else
{
s += str[i];   //进行老串的复制
}
}
length = s.size();    //对新串进行重新取其大小,对其进行遍历，逐个附回给老串
for (int i = 0; i < length; i++)
{
str[i] = s[i];
}

}
};