# Hijack Calculator

## Intro

The Hijack calculator allows you to perform basic calculations on your empeg, but it has
some serious limitations:
### Integer only

The calculator is integer only, both when entering numbers and when displaying results.
Any fractional part in a result is truncated. For instance 15/4 which should yeild 3.75 shows 3.
-15/4 shows -3.
### Priorities

Operation is infix, ie you pick the operator between entering the numbers, opposed to
postfix where you first enter the numbers and then the operator - common on HP calculators.
There is no prioritizing of */% over +- so an operation like 2+2*5 would yeild 20 (because it
is done as 2+2=4 *5=20) instead of 2+(2*5)=12 as the normal priority rules dictate.
## Operation

### Buttons

The calculator is controlled by the **Menu** and **Cancel** buttons (Rio remote) or the
**CD** and ***** buttons (Kenwood remote) as well as the number buttons (**0** to **9**).
The **Menu/CD** button acts as operator selector and the **Cancel/*** as Clear Entered,
Clear All and Quit.
### Display

The available operations and corresponding buttons are listed as a guide at the top two lines of
the screen in the following fashion:

Menu/CD: +-*/%=

Cancel/*: CE.CA.Quit

The two lower lines display previous (partial) result and the number you're currently entering,
respectively.

The currently selected operation is shown in the lower left hand corner.
### Available functions

The available mathematical operations are
- + : addition
- - : subtraction
- * : multiplication
- / : division
- % : modulus
- = : end calculation

### Using **Cancel/***

To clear an erroneous number entry (ie you meant to press **5** but mistakenly pressed **2**),
press **Cancel/*** once (CE, Clear Entered). The entire entered number is erased, not only the
last digit. You can not in this situation press **Menu/CD** to change the selected operation -
you can only enter another number.
If you press **Cancel/*** in the situation where the calculator expects either the first digit
of a number or another **Menu/CD** press (to change operator), the previous result will be
cleared (CA, Clear All).

Another press of **Cancel/*** in either situation above will quit to the Hijack menu.
## Examples of operation

### 12+5

enter **1** **2** with the number keys, press Menu/CD to go to operator selection.
+ is the first choice (default), so now you can enter the **5**. When you now press
**Menu/CD** the operation is carried out and the result, 17, is available for further
manipulation. If you want to start a new calculation (discarding the result) either repeatedly
press **Menu/CD** until the indicated operation is **=** or press **Cancel/***.
Then enter the first number of the new calculation.

### 12*15

enter **1** **2** with the number keys, repeatedly (3 times) press **Menu/CD** to
select the ***** operator.

Enter **1** **5** with the number keys, press **Menu/CD** to carry out the operation.

If you want to start a new calculation (discarding the result) either repeatedly press **Menu/CD**
until the indicated operation is **=** or press **Cancel/***. Then enter the first number of
the new calculation.

### (5+10-32)/5

enter **5** with the number keys, press **Menu/CD** once to select addition

enter **1** **0** with the number keys, press **Menu/CD** twice to select subtraction (15
is displayed)

enter **3** **2** with the number keys, press **Menu/CD** 4 times to select division
(-17 is displayed)

enter **5** with the number keys, Press **Menu/CD** (-3 is displayed, fractions are truncated)

If you want to start a new calculation (discarding the result) either repeatedly press **Menu/CD**
until the indicated operation is **=** or press **Cancel/***. Then enter the first number of
the new calculation.

### (5+10)-32%5

This would have to be entered in a different order, to make the calculations in the correct priority
order.

Press **Menu/CD** twice to select the **-** operator, enter **3** **2** with the number
keys

press **Menu/CD** 5 times to select the **%** operator

enter **5** with the number keys (-2 is displayed)

**+** is now selected (default), enter **5**, press **Menu/CD** (3 is displayed)

**+** is now selected (default), enter **1** **0** with the number keys, press
**Menu/CD** (13 is displayed)

### Continued operation on a result

If you wish to continue operating on a result (let's say multiplying 20 to the result of the last
example, (5+10)-32%5, above; do not select **=** and then press **Menu/CD**.
Don't press **Cancel/*** either.

Instead just press **Menu/CD** another 2 times to select the ***** operator and then enter
**2** **0** with the number keys and then press **Menu/CD** to perform the multiplication
(260 is displayed)