CSC212 Lab 2 2014

--D. Thiebaut (talk) 10:53, 9 September 2014 (EDT)

---

Problem 1: playing with ints and doubles

• Write a Java program that contains 3 ints and displays the sum of the 3 ints.
• Modify your program so that it creates 3 doubles and displays their products.

Problem 2: Strings

• Write a java program with a function called printBox(). The function receives a string as an argument, and displays the string between 2 lines of stars. For example:

String name = "Smith College";

printBox( name );

will print something like this:

*********************************
Smith College
*********************************

Note that the length of the lines of stars is fixed.

Problem 3: Loops

• Write a Java program that displays all the integers from -10 to +10, one per line.
• Write a Java program that displays all the positive multiples of 3 less than 30, starting with 3.
• Write a Java program that displays all the positive multiples of 3 less than 30, starting with 0.
• Write a Java program that displays all the negative multiples of 5 greater than -40.
• Write a Java program that displays all the powers of 2 less than a million, starting with 2.
• Write a Java program that prints the first 10 positive multiples of 3 and of 5, two per line, as shown below:

 3 5
 6 10
 9 15
 ...

• Write a Java program that where the function printBox() seen before actually puts a box around the string it prints. In order to get the length of the string received, the function can do this:

        int n = name.length();  // name is the string

Also, if you use System.out.print() instead of System.out.println(), you can put many strings/chars on the same line without going to the next line...

Problem 4: If statements

• Write a Java program that prints only the multiples of 3, 5 and 7 that are less than 500. To find if a variable n is divisible by 3, for example, you can do this:

if ( n % 3 == 0 ) {
     // n is a multiple of 3
}
else {
     // n is not a multiple of 3
}

• Write a java program that contains a function called min3( int a, int b, int c ) that returns the smallest of 3 integers. Test it on 3 different variables.
• Modify the same Java program, and add a new function called min3( double a, double b, double c ) that returns the smallest of 3 doubles. Verify that the java compiler does not complain about two functions/methods with the same name. As long as their list of parameters are different, Java is fine with it.

Problem 5: While loops

• Redo the questions of Problem 3 above, but using while loops only this time.

Submission to Moodle

Submit the Java program that prints a boxed string to Moodle.

• Login to Moodle and pick the CSC212 link
• Locate the Lab 2 activity in Week 2, Click on it.

• Note the information about the submission, and in particular the deadline (usually a week after you start on it).

• Click on the Edit Tab and copy/paste or type in your Java solution for the Lab. Make sure the name of the file is the same as the name of the file containing it. So, for this example, the class name is Lab2 (with an uppercase L), and the file name is Lab2.java.

• Click on Save to save your program in Moodle
• Click on Run to verify that your program runs correctly. A console window will open and show the program output.

If you have errors, correct them and repeat the previous 2 steps

• Once you are satisfied your program runs correctly, close the console window and click on Evaluate:

If everything ran smoothly, your program output matches that of the solution program, and you get a 100/100 grade, and a message indicating that your program passed 1 test out of 1. (In the future, your program may get tested with several different inputs).

• If your program output is not correct, then the Virtual Programming Lab module of Moodle will give you some indications:
  • The grade is 0/100
  • The correct output is shown
  • The output of your program is shown (and we can see the problem: a dash instead of a space)
  • A message indicating that your program failed 1 test out of 1.