剑指Offer_编程题_2

题目描述

请实现一个函数，将一个字符串中的空格替换成“%20”。例如，当字符串为We Are Happy.则经过替换之后的字符串为We%20Are%20Happy。

class Solution {
public:
	void replaceSpace(char *str,int length) {
        int oldStringLength;
        int numBlank = 0;
        for(oldStringLength = 0; str[oldStringLength]!='\0';oldStringLength++) {
            if (str[oldStringLength] == ' ') {
                numBlank++;
            }
        }
        int curStringLength = oldStringLength + numBlank * 2;
        if (curStringLength > length) return;
        str[curStringLength] = '\0';
        for(int j = oldStringLength-1,i = curStringLength-1; j != i; j--) {
            if (str[j] == ' ') {
                str[i] = '0';
                str[i-1] = '2';
                str[i-2] = '%';
                i = i-3;
            } else {
                str[i] = str[j];
                i--;
            }
        }
	}
};