I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.
See this post to find the backtick on your keyboard. The “preformatted text” tool in the editor (</>) will also add backticks around text.
After reading one word, the next thing in the stream is the end-of-line character. That’s what your getline is taking as input. getline input is terminated by the end-of-line character.