剑指offer-0x04

#include <iostream>

using namespace std;

void ReplaceBlank(char str[], int length)
{
    if(str == NULL || length<=0)
        return;
    int originalLength = 0;
    int numofBlank = 0;
    int i = 0;
    //计算原字符串的长度，并统计空格个数
    while(str[i]!= '\0')
    {
        originalLength ++;
        if(str[i] == ' ')
            numofBlank ++;
        i++;
    }
    //每替换一个空格，长度增加2
    int newlength = originalLength + numofBlank * 2;
    if(newlength>length)
        return;
    int indexofOriginal = originalLength;
    int indexofNew = newlength;

    while(indexofOriginal>=0 && indexofNew>indexofOriginal)
    {
        if(str[indexofOriginal]==' ')
        {
            str[indexofNew--]='0';
            str[indexofNew--]='2';
            str[indexofNew--]='%';
        }
        else
            str[indexofNew--]=str[indexofOriginal];
        indexofOriginal--;
    }


}

int main()
{
    char str[]="hello world hello c++";
    ReplaceBlank(str,100);
    cout << "result is  "<< str<<endl;
    return 0;
}