Project
Your project will consist of programming a basic 4 function calculator with an on and off button. Such task usually primitive and essay to implement however the thing that will make it a challenge is to correctly utilize the Graphical user Interface to simulate a device from real life.
States
On and Off
As you might have noticed, the calculator can either be tamed on, or fumed off. If the calculator is turned on then actions or events will have to he handled as they occur, however if the calculator is turned off nothing should happen (as in no clicks or button events should register or display some form of change) unless the on button is pressed. To do this you will need to simulate an on and off state, which .n be distinguished with a Boolean value. To make use of that value, you will need to declare it at the class level (the b.) and initialize ifs value once the form launches.
Value held by display
Like Me On and Off states that need to be programmed, you will also need to change what is displayed when you input a new value. The default value that should be displayed when the calculator is fumed on is V. but you can't have your value start with a "0" can you? To overcome this problem, you will need to make two different states that determine what the display (label) should hold. A transition states that either displays the previous value or a O. and an input state that displays. value being inputted each time a Mon b pressed. So, basically you sled at the transition state when you tam on the calculator or click one of the 0 functions. Men you start inputting numbers, the state changes from transition to input.
Logic
Instance variable (instance level scope) current value
You should have a variable that stores the value of your calculation every time you need to input a new number.
A instance level Function and Variable to determine the operation needed every time an operation is activated
Make a function that takes in a variable declared at the Instance level which determines the operation to be made, and current value so that the result Is shown on the display every time a function Is activated
Avoiding multiplication on 0 when re/initializing the calculator.
When you ...turn on the calculator the default value is O. If you want to do a multiplication operation on Nat zero then you will have to add N. zero to whatever number you input. In other wo.s, the default value is zero and the default operation is add.
Buttons and events
Buttons 1-9:
If ofr do nothing
else
if in transition state: Clear the display and append the it's text with the number represented by the button then change the stale from transition to input
else: just append the display
Button 0:
If Off do nothing
else
if transistion state set display to display only "0".
else append the display with zero
Button (function x + - / = ):
If off do nothing
else
If transition state stay In transition state and don't change
else compute the value based on current value and input value (and previous operation)
Button ON
If state is off then initialize the calulator to default settings else do nothing
Button OFF
If state Is OFF then do nothing
else: clear display and charge state to off
Button C
If ON state Clears everything and initializeto default settings else do nothing
Button CE
If ON state Clear the current entry to (but not the current calculated value)
What it should look like in the end.
It should look something like this. Doesn't have to be exact so get trestive
