Java Coding Problems

6. Counting the occurrences of a certain character

A simple solution to this problem consists of the following two steps:

1. Replace every occurrence of the character in the given string with "" (basically, this is like removing all of the occurrences of this character in the given string).
2. Subtract the length of the string that was obtained in the first step from the length of the initial string.

The code for this method is as follows:

public static int countOccurrencesOfACertainCharacter(    String str, char ch) {  return str.length() - str.replace(String.valueOf(ch), "").length();}

The following solution covers Unicode surrogate pairs as well:

public static int countOccurrencesOfACertainCharacter(    String str, String ch) {  if (ch.codePointCount(0, ...