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Language/Type: VB recursion string return

Write a recursive function named ReplaceAll that accepts three parameters: a string s, a char from, and a char to as parameters, and returns a new string that is the same as s but with any occurrences of from changed to to. For example, the call of ReplaceAll("crazy raccoons", "c"c, "k"c) should return "krazy rakkoons" and the call of ReplaceAll("BANANA", "A"c, "O"c) should return "BONONO".

Your function is case-sensitive if the character from is, for example, a lowercase "f"c, your function should not replace uppercase "F"c characters. In other words, you should not need to write code to handle case issues in this problem.


  • Do not use any loops; you must use recursion.
  • Do not declare any global variables.
  • Do not call the string member functions IndexOf, Contains, Replace, or Strings.Split. (The point of this problem is to solve it recursively do not use a library function to get around recursion.)
  • Do not use any auxiliary data structures like List, Dictionary, etc.
  • You can declare as many primitive variables like integers as you like, as well as strings.
  • You are allowed to define other "helper" functions if you like they are subject to these same constraints.
Function: Write a VB function as described, not a complete program.

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