package com.dj;

public class Utilities {

//Returns a char containing every nth char. When

// sourceArray.length() < n, returns sourceArray

public char[] everyNthChar(char[] sourceArray, int n) {

if (sourceArray == null || sourceArray.length < n) {

return sourceArray;

}

int returnedLength = sourceArray.length / n;

char[] result = new char[returnedLength];

int index = 0;

for (int i = n-1; i < sourceArray.length; i += n) {

result[index++] = sourceArray[i];

}

return result;

}

//Removes pairs of the same character that are next

// to each other, by removing one occurrence of the character.

// "ABBCDEEF" -> "ABCDEF"

public String removePairs(String source) {

//If the length is less than 2, there won't be any pairs

if (source == null || source.length() < 2) {

return source;

}

StringBuilder sb = new StringBuilder();

char[] string = source.toCharArray();

for (int i = 0; i < string.length - 1; i++) {

System.out.println(string[i]);

if (string[i] != string[i + 1]) {

sb.append(string[i]);

}

}

System.out.println(string[string.length -1]);

// Add final character that will always be safe

sb.append(string[string.length - 1]);

return sb.toString();

}

// perform a conversion based on some internal

// business rule

public int converter(int a, int b) {

return (a/b) + (a * 30) - 2;

}

public String nullIfOddLength(String source) {

if (source.length() % 2 == 0) {

return source;

}

return null;

}

}