C++:利用string类编程，输入一句英文，统计一英语句子中单词的个数

#include <string>#define BUFLEN 1024using namespace std;bool isWord(char);int main() {char line[BUFLEN];string str;int word = 0, begin = 0;cin.getline(line, BUFLEN);str = line;for (int i = 0; i < str.length(); ++i) {if (str[i] == ' '){if (isWord(str[begin]))++word;begin = i + 1;}}while (str[begin] == ' ')++begin;if (isWord(str[begin]))++word;cout << "句子中包含的单词个数：" << word << endl;return 0;}bool isWord(char ch) {return ((ch >= 'A' && ch <= 'Z') || (ch >= 'a' && ch <= 'z'));}