अंतिम कार्य

Sometimes a task is just a task. With no dirty tricks, and no need to look for complexity or depth. You just need to sit down and do it. Just such a task is before us. See how everything is clear and simple: create an array whose elements are lists of strings. And then fill the array with any data and display it on the screen.

Searching for duplicates and matches is a favorite exercise for programmers. Let's do this: use the keyboard to read a list of 20 words and count how many identical words the list contains. We'll represent the result as a Map, where the key is a unique string, and the value is the number of times this string occurs in the list.

Once upon a time there was a list of integers. Everything would have been fine, but it lacked a method to safely retrieve the numbers. Take pity on the list and create such a method for it. It must return a list item based on its index. If an exception occurs while retrieving an element, it must be caught, and the method should return defaultValue.

Other people's mistakes once again block our path to a brighter future. On the contrary, maybe they actually form the path: it's hard to become a programmer without them. Take this non-functioning program and rework it so it compiles. It demonstrates how a HashMap works: read pairs (a number and string) from the keyboard, put them in a HashMap, and then display its contents.

Old task: Read pairs (a number and string) from the keyboard, and then display them on the screen. New task: Read the same pairs from the keyboard and store them in a HashMap. Any empty input string signifies the end of data entry. The numbers can be repeated, but not the strings. The entered data must not be lost! Then the program should display the contents of the HashMap on the screen, each pair on a new line.

We received a new children's assignment from the ordered isomorphs on Planet Linear Chaos. You remember that it was these weirdos who thought up all sorts of sorting techniques and constantly practice them. That's why these tasks are so strange. Check it out: read 30 numbers from the keyboard. Display the 10th and 11th smallest numbers. But, you know, you've got to try it!