5.2

5.4

 while (string::iterator iter != s.end()) { /* . . . */ } 改正：std::string::iterator iter = s.begin();while (iter != s.end()) { /* . . . */ }

while (bool status = find(word)) { /* . . . / } if (!status) { / . . . */ }status是while语句的局部变量，if无法访问改正：while (bool status = find(word)) {     /* ... */     if (!status) { /* ... */ }}