An Overview of Decimal BASIC


Inputting a program and execution

When BASIC.EXE starts, the editor screen appears.
The keyword "END" is already inserted.

A program shall be inputted.
Line numbers can be omitted.

Another window, which displays the outputs, appears when a program start running.

This window has the same facility as an editor.
You can scroll the screen to see any part of the output.
A result can be saved to a file or handed over to another application by using the clipboard.


Plotting a graph

If you want to plot the graph of a function, you start with coordinating the plane.

If we want to coordinate the screen to make the x-coordinate of the left end left, the x-coordinate of the right end right, the y-coordinate of the lower end bottom, the y-coordinate of the upper end top, respectively, we use a set-statement of the following form.

 SET WINDOW left , right , bottom , top 

The instruction which commands to plot the points (x, y) with lines is shown below.

PLOT LINES: x , y ;

If we draw the coordinate axes, we use an original enhancement DRAW AXES or DRAW GRID.

Now, we draw a graph of a function y = x3-3x.

If we run a program that uses graphics facilities, a window that displays the graphics output appears.

The coordinates of the point that the mouse indicates are shown on the lower margin of the window.

Graphics results can be saved to files or transferred to other applications via the clipboard.


Debugging

A sample program chaos1.bas is executing.

We can break an executing program at any moment by pressing the break button (or choose break on the menu).

When execution of a program is broken, A debug window appears. The debug window shows every value of variables and the statement that shall be executed next. The variables shown over the line on the upper area are the local variables of the internal procedure. On the edit window, the corresponding line shall be colored green.


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