ことか to place strong emphasis on something?


According to this website (<http://www.jlptsensei.com/grammar-lesson/kotoka/>)
"ことか is used to place strong emphasis on something." This is the only
explanation I could find. I was wondering if that is a common expression and
in what context would you use it? Thank you.




The ことか is used in an exclamatory sentence (感嘆文) , usually preceded by an
interrogative word such as どんなに, どれほど, なんと, 何度 etc.

Examples:

>   * **どんなに** うれしい **ことか** ！ (≂ どんなにうれしいだろう！)  
>  How happy I would be!
>   * **なんと** 美しい **ことか** ！ (≂ なんと美しいのだろう！ / なんて美しいんだろう！)  
>  How beautiful it is!
>   * **何度** 失敗した **ことか** ！ (≂ 何度失敗しただろう！)  
>  (I have no idea) How many times I have failed!
>

(「～～ことか！」 sounds a bit more literary than 「～～だろう！」)

