（二）剑指Offer之替换空格

class Solution {
public:
void replaceSpace(char *str,int length) {
if(str == NULL || length <= 0)
return;
int originalLength = 0;
int numberOfSpace = 0;
int i=0;
while(str[i] != '\0'){
++ originalLength;
if(str[i]==' ')
++ numberOfSpace;
++i;
}
int newLength = originalLength + 2*numberOfSpace;
if(newLength > length)
return;
int originalIndex = originalLength;
int newIndex = newLength;
while(originalIndex >= 0 && newIndex > originalIndex){
if(str[originalIndex] == ' '){
str[newIndex--] = '0';

4000
str[newIndex--] = '2';
str[newIndex--] = '%';
}
else
str[newIndex--] = str[originalIndex];
--originalIndex;
}
}
};