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6 caculate

boolean

using Boolean values and logic to produce a result

program requirement

Some AI (artificial intelligence) apps are used to help humans complete decision making by using logic. The boolean values true and false can be used in expressions which have logic operations instead of arithmetic operations.

Equipment safety checks will pass overall when all the individual components test safe.

This program should ask the user to enter the safety of two components. The program should use logic operations to produce the overall safety result. The final safety result should be displayed.

learning point

You will remember that there are two boolean values: true, false

There are three basic logic operations (AND, OR, NOT) and are defined like this:

true AND true produces true

true AND false, false AND true, false AND false all produce false

true OR false, false OR true, true OR true all produce true

false OR false produces false

NOT(true) produces false

NOT(false) produces true

in java AND is coded as &&, OR is coded as || and NOT is !

expected output

Does the front light turn on? true

Does the back light turn on? true

Bike safe to ride: true

understanding the output

the user has entered two boolean values, both are true

the program has used logic that uses a rule which says a bike is only safe when both the front light and the backlight operate successfully

introducing the code

1 boolean frontLightOK = false;

2 boolean backLightOK = false;

3 boolean bikeLightsOK = false;

// INPUT

4 System.out.print("Does the front light turn on? ");

5 frontLightOK = Boolean.parseBoolean(keyboard.nextLine());

6 System.out.print("Does the back light turn on? ");

7 backLightOK = Boolean.parseBoolean(keyboard.nextLine());

// PROCESS

8 bikeLightsOK = frontLightOK && backLightOK;

// OUTPUT

9 System.out.println("Bike safe to ride: " + bikeLightsOK);

understanding the code

lines 1-3 the boolean variables are initialised to false, also described as setting them to clear

lines 4-7 the user is prompted to enter two boolean values for the state of the font and back lights

line 8 includes the expression frontLightOK && backLightOK

this expression includes the AND logic operator so the result will be true when both variables are true, otherwise the result is false

the boolean result is then assigned to the variable bikeLightsOK

line 9: displays the value of the boolean variable bikeLightsOK

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the program code

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PRIMM

predict

Read the code and assume the user enters the value true for both the front and back lights

run

go ahead and run the program, enter the example values used above, then run the program again and enter your own test values

look at the results displayed by the program, these are called the actual output

check that the expected output is the same as the actual output

investigate

try out the other 3 combinations of boolean values for the bike lights: true/false, false/true and false/false

compare the results you see with the learning points

look at the

test.md⁠

file in the project frame for a full test plan

try changing the logic operators from AND to OR, replace the && operator with ||

run the program again with the same test values for the bike lights

compare the output with the original results and the learning points

change the operators back to AND &&

modify

Move directly on to the make task

make

Computers and laptops can have several ways to make a connection to a network like the Internet. Many will have both a WiFi interface and also an ethernet (wired) interface. So there will be a network connection available when either or both interfaces are active.

requirement

Can you create an Input-Process-Output sequence to calculate the number of flights still left to climb and the average per day to reach the target. The output dialog would look like this.

Is the WiFi interface active?: false

Is the ethernet LAN interface active?: true

Network connetion available: true

Think carefully about how you would do the calculation and what types of data and what variables would be involved. WHat logical operator should you use?