Write a function in C progarmming language that gets a string str, changes all lower case letters to * (asterisk), and all upper case letters to $ (dollar sign). All other characters remain unchanged....

Write a function in
C progarmming language
that gets a string str, changes all lower case letters to * (asterisk), and all upper case letters to $ (dollar sign). All other characters remain unchanged. The function returns the total number of letters modified.

int hide_letters(char* str);

For example:

• 
  

  -  If str is "12ab0", then the function changes it to "12**0", and returns 2.

  
  


• 
  

  -  If str is "aBCDe*", then the function changes it to "*$$$**", and returns 5.

  
  


• 
  

  -  If str is "0123&***", then the function keeps the string as is, and returns 0.

  
  


• 
  

  -  An empty string is also a string.