Algorithms and Data Structures in an Object-Oriented Framework (“ADSOOF”)

Code for “Java's built-in classes” section

Code demonstrating Strings

• ScannerTest1.java Demonstrates using a Scanner object to break a line of text into individual words.
• ScannerTest2.java Demonstrates using a Scanner object to break text from a file into individual lines.
• StringTest1.java Shows and demonstrates a static method which takes a string and two characters and returns the string given by replacing all occurrences of the first character in the string by the second character.
• StringTest2.java Demonstrates the same operation as in StringTest1.java, but done using one of Java's built-in non-static String methods (so the method is called on a string rather than the string passed as an argument to it).
• StringTest3.java Demonstrates using the built-in string method substring.
• StringTest4.java Demonstrates using the built-in string methods startsWith, endsWith and compareTo.
• StringTest5.java Demonstrates using the built-in string methods indexOf and lastIndexOf.
• StringTest6.java Demonstrates using the built-in string methods toUpperCase and toLowerCase.
• StringTest7.java Demonstrates converting arrays to strings and vice-versa.
• StringTest8.java Demonstrates using the method toBinaryString from wrapper class Integer.
• StringTest9.java Demonstrates using some methods from wrapper class Character.
• StringTest10.java Shows and demonstrates the implementation of a method which performs the startsWith operation as in StringTest4.java, but as a static operation, so both strings are arguments. Method is implemented using iteration.
• StringTest11.java Shows and demonstrates a method which perfoms the same operation as in StringTest10.java, but is implemented using recursion rather than iteration.
• StringTest12.java Shows and demonstrates a method which perfoms the same operation as in StringTest10.java, with the tail recursion of StringTest11.java converted into iteration.
• StringTest13.java Shows and demonstrates a method which performs the same operation as in StringTest1.java, but is implemented using recursion and not iteration.
• StringTest14.java Shows the difference between == and equals with strings.

Code demonstrating ArrayLists

• UseArrayLists1.java Demonstrates a static method which takes an arrayList of integers as an argument and two integers and changes all occurrences of the first integer to the second destructively. Numbers entered into the arrayList as if it were an array.
• UseArrayList2.java Demonstrates a static method which takes an arrayList of integers and returns a copy, using the add method from class ArrayList.
• UseArrayList2a.java Demonstrates using clone to make a copy of an arrayList.
• UseArrayList3.java Demonstrates making a copy of an arrayList of integers using the constructor which takes an arrayList argument from class ArrayList.
• UseArrayLists4.java Demonstrates a static method which takes an arrayList of integers and two integers as arguments and inserts the second integer after all occurrences of the first integer, doing it destructively.
• UseArrayLists5.java Demonstrates a version of the static method in UseArrayLists4.java which does not go into an infinite loop when both argument integers are the same.
• UseArrayLists6.java Demonstrates a static method which takes an arrayList of integers and two integers as arguments and inserts the second integer after all occurrences of the first integer, doing it constructively (that is, returns a new arrayList with the required changes).
• UseArrayLists7.java Demonstrates a version of the static method in UseArrayLists6.java which avoids unnecessary repeated calls of the method get.
• UseArrayLists8.java Demonstrates a static method which takes an arrayList of strings and two strings as arguments and inserts the second string after all occurrences of the first string, doing it constructively. So, same operation as UseArrayLists7.java, but deals with strings rather than integers.
• UseArrayLists9.java Demonstrates the use of two static methods which take an arrayList and two objects of its base type, and insert the second object after all occurrences of the first object constructively. In one case, the base type is integers, in the other strings.
• UseArrayLists10.java Demonstrates the use of a single static methods which take an arrayList and two objects of its base type, where the static method has a type variable to give the base type. The method is called twice, the first time setting the type variable to Integer, the second time setting it to String.
• UseArrayLists11.java Demonstrates calling various static methods which take arrayLists as arguments, taking them from a separate class of static methods.
• UseArrayLists12.java Demonstrates removal of a particular integer from an arrayList of integers and removal of an integer from a particular position (the two different forms of the remove method).
• UseArrayLists13.java Same as UseArrayLists12.java, but uses an arrayList of strings instead of an arrayList of integers.
• UseArrayLists14.java Demonstrates a static method which takes an arrayList of integers and an integer as its arguments and removes destructively each integer which occurs before each occurrence of the integer argument. It removes the integer argument itself when it occurs before another occurrence of itself.
• UseArrayLists15.java Same as UseArrayLists14.java>, but does the operation constructively instead of destructively.
• ArrayListOps A class of static methods which work on arrayLists and are generic so they will work on arrayLists of any base type. There are methods to reverse an arrayList, to take an arrayList and two objects and change all occurrences of the first object in the arrayList to the second object, and to take an arrayList and two objects and insert the second object after all occurrences of the first. There are destructive and constructive versions of each method.

Code demonstrating generics

• GenericArrayTest.java Demonstrates a generic method to find whether an item is present in an array of items of that type, with the method used for an array of Strings and an array of Integers.
• UseArrayLists16.java Demonstrates a generic static method which takes an arrayList of objects as an argument and two objects of its element type and changes all occurrences of the first object to the second destructively. To use this code you also need the .class files:
  • Pair.class A class of pairs of integers
  • NoPairException.class An exception class
• UseArrayLists17.java Demonstrates the difference between comparing two object references using equals and using ==

Text files

Text files, to be used as data for exercise.

• twinkle.txt
• jabberwocky.txt
• mlk.txt

Last modified: 16 July 2019