逆序替换空格 -- 剑指offer

#include<iostream> using namespace std;void ReplaceBlank(char str[], int length){if(str==NULL || length <= 0){return;}int originalLength = 0;int numberOfBlank = 0;int i = 0;while(str[i]!='\0') {++originalLength;if(str[i]==' '){++numberOfBlank;}++i;}int newLength = originalLength + numberOfBlank * 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 source[100] = {"we are happy."};cout << "Before replacing balank: " << source << endl;ReplaceBlank(source,100);cout << "After replacing balank:  " << source << endl;}