Lab 6.1 — Vaccination — Take 2 (Vaccination) (Approval)
Modify Program 6.1 to use the
&& operator instead of the
|| operator
Sample Test Run #1
Enter patient's age: 2
***** Do NOT ADMINISTER VACCINE *******
Sample Test Run #2
Here is a sample execution of the program.
User input is in bold. Your program should replicate the prompts and output:
Enter patient's age: 3
Go ahead and stick it to 'em
- Emphasizing the equivalence of && and || logical expressions (with the additional use of !)
- You can use your own logical common sense to do this, but try using DeMorgan's law instead
Lab 6.2 — Vaccination — Take 3 (Vaccination)
Modify Program 6.1 (or Lab 6.1) so that the gender of the patient (M/F) is entered, and taken into account, as well.
The vaccine should NOT be administered to those patients who match one of the categories
in the following table ( a '-' means that no distinction is made for that column):
| Age
| Gender
|
| Under 3
| -
|
| 20-45
| F
|
| Over 65
| -
|
Sample Test Run #1
Enter patient's age: 2
Enter patient's gender: M
***** Do NOT ADMINISTER VACCINE *******
Sample Test Run #2
Here is a sample execution of the program.
User input is in bold. Your program should replicate the prompts and output:
Enter patient's age: 64
Enter patient's gender: F
Go ahead and stick it to 'em
- More complex logical expressions / conditions
Lab 6.3 — Divisibility Again (Divisibility)
Write a program containing a method
boolean divisibleBy17(int n)
that returns
true if
n is divisible by 17 and
falseotherwise.
Your
main should prompt the user for an integer, pass it to the method and print the returned
boolean value. (This is a variation of Program 3.1).
Sample Test Run #1
Enter number for which to check divisibility by 17: 17
17 is divisible by 17
Sample Test Run #2
Enter number for which to check divisibility by 17: 15
15 is not divisible by 17
- Practice using boolean-valued methods
Lab 6.4 — Divisibility Again — Take 2 (Divisibility)
Rewrite Lab 6.4 so that the method is now
boolean isDivisible(int n, int m).
isDivisible returns
true if
n is divisible by
m.
Again your
main should read in the two numbers, pass them to the method and print the result.
Sample Test Run #1
Enter number to be checked: 10
Enter number to be divided by: 5
10 is divisible by 5
Sample Test Run #2
Enter number to be checked: 3
Enter number to be divided by: 2
3 is not divisible by 2
- A more general version of the method of the previous lab … this one tests for general divisibility of one number by another, not just by 17.
Lab 6.5 — Evenness (Evenness) (Approval)
Write a program that contains two methods:
- the
isDivisible method of Lab 6.4
- a method,
boolean isEven(int n), that returns whether n is even or not
isEven must be written using isDivisible
- (This is an example of method composition discussed in the notes)
Your
main should prompt for the number, pass it (to
isEven, and
print the result.
Sample Test Run #1
Enter number to be checked: 12
12 is even
Sample Test Run #2
- In this exercise you are using the logic of one method (
isDivisible) to
facilitate the writing of another method (isEven).
- This is known as
leveraging; i.e., the existence of the first method makes the
writing of the second method easier.
- But it's more than simply easier; assuming you have tested the first method,
if most of the work of the second method is shunted to that first method, the second method will be
more repliable as well.
- In this particular case, the logic of neither method is all that involved (i.e., even without relying on
isDivisible, isEven
would be fairly easy to code), but this is meant as an introductory example.
Lab 6.6 — Evenness - Take 2 (Evenness) (Approval)
Rewrite Lab 6.5, but this time, assume the method
isDivisible already exists and is in the class
Utilities
Sample Test Run #1
Enter number to be checked: 12
12 is even
Sample Test Run #2
- Some practice calling methods from outside the class
- We've done this before; this is no different than our calling the
sqrt methof of the Math class
isDivisible is invoked the same way as Math.sqrt, expcept it class name is Utilities
Lab 6.7 — Fun with Numbers (InfoOf3) (Approval)
Write a program that reads three numbers from the keyboard, and then prints out some information about
the relationships between the numbers-- whether they are all equal, in ascending order,
in descending order, and so on. To determine these relationships, write the following
boolean-valued functions:
boolean allAreEqual(int a, int b, int c);
boolean twoAreEqual(int a, int b, int c); // false if all three are equal
boolean noneAreEqual(int a, int b, int c);
boolean areAscending(int a, int b, int c); // true if a <= b <= c
boolean areDescending(int a, int b, int c); // true if a >= b >= c
boolean strictlyAscending(int a, int b, int c); // true if a < b < c
boolean strictlyDescending(int a, int b, int c); // true if a > b > c
Try to "talk boolean"
Sample Test Run
first number? 1
second number? 2
third number? 3
allAreEqual: false
twoAreEqual: false
noneAreEqual: true
areAscending: true
areDescending: false
strictlyAscending: true
strictlyDescending: false