【面试准备】字符串反序

#include <iostream>
#include <string>
#include <stdlib.h>
using namespace std;

void reverseWords(string &s) {
string a[s.length()];
int j = 0;
int aa = 0;
int i = 0;
char *w = (char*) malloc(s.length());
for( i = 0 ; (unsigned)i < s.length(); ++i){
if(s.at(i)!=' '){
w[j++] = s.at(i);
}
if(s.at(i)!=' '&&((unsigned)i+1 == s.length()||s.at(i+1) == ' ')){
w[j] = '\0';
j = 0;
a[aa++] = w;
}
}
for(int i = aa-1 ; i >= 0 ;--i){
cout<<a[i]<<" ";
}
}

int main(){
string s = "the sky is blue";
reverseWords(s);
return 0;
}