title: How to count the number of uppercase letters, lowercase letters, and digits in a string?
body: <p>I want to write a program in C++ which gets a string from the user and outputs the number of uppercase letters, lowercase letters and digits.</p>
  <p>e.g. for input &quot;aKb12CD34&quot; the result should be 2 lowercase letters, 3 uppercase letters, and 4 digits.</p>