Calculator Display

The calculator display has a number of built-in features, including the ability to show numbers in different modes as defined in the Mode dialog tab, and in different decimal formats. It can also display arrays of numbers or matrices, which is further explained in the Matrix/Array Functions section.

Setting the Display Options

Using the Display page of the Options dialog, you can select the type of decimal display - normal (or floating point), fixed-point, scientific, or engineering. You can also choose the number of digits, which for scientific means the number of significant figures, and in fixed-point means the number of digits after the decimal point.

Note that if you compute a number in fixed-point display the value is not rounded at each step (i.e. numbers are internally stored to the maximum precision available). This can occasionally be a problem in financial calculations if the existence of the extra precision is overlooked. Be careful not to increase the number of digits too far if the display font is large, otherwise there is a danger that significant digits (or worse, the exponent!) may be overlooked, particularly in scientific or exponent display mode. Digits which are not visible because they lie outside the display area can be seen by using the cursor to increase the size of the calculator. The display re-sizes itself automatically when the calculator window is re-sized.

Other customizable features of the display are the font and background colour. Again, care is needed when changing font, as too large a font at higher precision may result in digits falling outside the boundaries of the display.

Normal Display Format

This is effectively floating point, until the number is too large or too small to display as a floating point number given the size of the display, at which point the number is presented using Scientific format (i.e. as exponent and mantissa).

For floating point numbers, the Digits edit box specifies the maximum total number of digits displayed.

Fixed Display Format

The number is displayed with a fixed number of decimal places, determined by the value in the Digits edit box.

Scientific Display Format

In Scientific format a number is displayed as an exponent and a mantissa in the range 1.0 to 9.999 (recurring, to the available number of digits). (i.e. as exponent and mantissa). The number of significant digits is specified by the Digits edit box.

Engineering Display Format

This is the same as Scientific format except the mantissa is adjusted so that the exponent is always a multiple of three. e.g. 1.234e5 is displayed as "123.4e3". The number of significant digits is specified by the Digits edit box.

Display of non-decimal numbers

The statistics mode is equivalent to decimal mode for the purposes of number display.

When the calculator is in financial number mode, the display format is fixed point with two decimal places. Commas can be enabled for thousands using the checkbox, e.g. "10000.00" can be made to display as "10,000.00".

For Binary, Octal, Hexadecimal and Base-N modes, the number is displayed in the appropriate format. Fractional parts of numbers are not displayed in these modes. The interpretation of signed numbers is determined by the state of the Base Signed checkbox. If checked, negative numbers are displayed as signed numbers. If not checked, numbers are displayed as if they were unsigned.

Angle and Time modes cause the number to be displayed as a sexagesimal number.

Other Display Properties

Numbers can be Left, Centre or Right justified within the display (or display cell in array mode).

The colour of the cell background can be changed using the first of the three colour wells (the other two are used in array mode). Click on the colour well with the mouse to obtain the colour selection dialog. The foreground colour is changed as part of the Font dialog which is obtained by pressing the Font button. This allows the size, type and colour of the font used to be changed.

Displaying Arrays and Matrices

When using arrays of numbers (see the section on the Mode dialog tab), the display is divided into a number of array cells on a grid. The colour of this grid is set by the bottom of the three colour wells.

The dimensions (in pixels) of each grid cell is defined by the Array Cells Width and Height edit boxes.

The axes are drawn using the font specified using the Font dialog obtained by pressing the Axis Font button. The axis background is set using the middle of the three colour wells.