C++Tom从小就对英文字母非常感兴趣，尤其是元音字母(a,e,i,o,u,A,E,I,O,U)，他在写作文的时候都会把元音字母写成大写的，辅音字母则都写成小写, 你试试把一个句子翻译成他写作文的习惯吧。 请使用字符串流解决该问题，需要有main函数，要有注释（最好英文） 输入一个字符串S(长度不超过100，只包含大小写的英文字母和空格)。

Here is the code in C++:

#include <iostream>
#include <sstream>
#include <string>
using namespace std;

int main() {
    string s; // declare a string variable to store the input
    getline(cin, s); // read a line of input from the console

    stringstream ss(s); // create a stringstream object with the input
    string word; // declare a string variable to store each word in the input

    while (ss >> word) { // read each word from the stringstream
        for (int i = 0; i < word.length(); i++) { // iterate through each character in the word
            if (word[i] == 'a' || word[i] == 'e' || word[i] == 'i' || word[i] == 'o' || word[i] == 'u' ||
                word[i] == 'A' || word[i] == 'E' || word[i] == 'I' || word[i] == 'O' || word[i] == 'U') {
                // if the character is a vowel, convert it to uppercase
                word[i] = toupper(word[i]);
            } else {
                // otherwise, convert it to lowercase
                word[i] = tolower(word[i]);
            }
        }
        cout << word << " "; // output the modified word with a space
    }

    return 0;
}

Explanation:

1. We first declare a string variable `s` to store the input.
2. We read a line of input using `getline(cin, s)`.
3. We create a `stringstream` object `ss` with the input string `s`.
4. We declare a string variable `word` to store each word in the input.
5. We use a `while` loop to read each word from the `stringstream` using `ss >> word`.
6. For each word, we iterate through each character using a `for` loop.
7. If the character is a vowel (either lowercase or uppercase), we convert it to uppercase using `toupper()`.
8. Otherwise, we convert it to lowercase using `tolower()`.
9. We output the modified word with a space using `cout << word << " "`.
10. The program terminates after all the words have been processed.