c++ - 输入流与 C++ 中的 getline

Question

我有一个字符数组char input[11];。我有一个循环：

do {
  is >> input;      // is is an input stream defined by istream& is
} while (something)
// works fine

do {
  is.getline(input, 11);
} while (something)
/* i enter 10 digits and press enter, cursor still blinks,
i enter another value and finally it proceeds to the next piece of code */

两者有什么区别，为什么一个读入所有 11 个字符（10 个数字 + 回车）而另一个悬空？