Introductory Programming In Java

Lab 2

Objectives

Write a few small Java programs which require to use conditional structures, operators and loops.

Exercise One

Write a program to print out the last digit of an integer seven times the value of an integer which the user enters.

For example, if a user enters the number '53', your program will compute the number 7*53=371 and print out the last digit which is '1'.

(Note that you will need to use the modulo operator (%) in this program.)

Exercise Two

• An examiner using a grading scheme whereby the grade depends on the marks thus:

      
  0-50   F
  51-60  E
  61-70  D
  71-80  C
  81-90  B
  91-100 A
  

  Write a program that asks for a score (0-100) and reports the grade (F-A).

• Refine the previous program by making it to add a '+' or '-' after the grades E and above according to last digit as follows:

  1-3   -
  4-7    
  8-0   +
  

  This means that a mark of 93 is A-; 88 is B+; 65 is D and so on.

Exercise Three

• Write a program that asks the user for a positive integer n and prints out the n×n grid like this (when n is 4):

  +--+--+--+
  |  |  |  |
  +--+--+--+
  |  |  |  |
  +--+--+--+
  |  |  |  |
  +--+--+--+
  

  You should have one method to print the even rows and one method to print the odd rows.

• Write a similar program which prints out a triangle:

      +
     /|
    / |
   /  |
  +---+
  

Further programming ideas

Different functionalities of your programs (like calculating a desired number, or determining a grade, or printing a result etc), should be implemented with the help of different methods: this is called modularization — one of the basic principles of programming. If you did not use methods in our coding solutions, but lumped everything into one main method, then re-implement everything using modularization.