替换空格

class Solution {
public:
    void replaceSpace(char *str,int length) {
       // char * p =str;
        int i,j;
       for(i=0;i<length;i++)
       {
           if(str[i]==‘ ‘)
           {
               for(j=length-1;j>i;j--)
                   str[j+2]=str[j];
               str[i]=‘%‘;
               str[i+1]=‘2‘;
               str[i+2]=‘0‘;
           }
       }
 
    }
};

class Solution {
public:
    void replaceSpace(char *str,int length) {
        if(str == NULL||length <0) return;
        int oldlength = 0;
        int newlength = 0;
        int space_num = 0;
        for(int i = 0;str[i]!=‘\0‘;++i)
        {
            ++oldlength;
            if(str[i]==‘ ‘)
            {
                ++space_num;
            }       
        }
        newlength = oldlength + space_num*2;
        if(newlength>length) return;
        while(oldlength>=0)
        {
            if(str[oldlength]!=‘ ‘)
            {
                str[newlength--] = str[oldlength];
            }
            else
            {
                str[newlength--]=‘0‘;
                str[newlength--]=‘2‘;
                str[newlength--]=‘%‘;
            }
            --oldlength;
        }
        return;

    }
};