Radio Shack TRS-80 - Appendix 0; Sample Programs

Computer Graphics
Operation Manual
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Appendix D/ Sample Programs
BASICG
l~ ,
2~ , Pie Graph Program ("pECANPIE/GRA")
3~ ,
4~ , Object
5~' The object of this program is to draw a pie graph of the
6~' expenses for a given month of eight departments of a company,
7~' along with the numerical value of each pie section
8~' representation.
9~ ,
l~~ ,
ll~ , Running the program
l2~' The month and the amounts spent by each department are input,
l3~' and the program takes over from there.
l4~ ,
l5~ , Special features
~ l6~' The amounts spent by each account as well as the total
l7~' amount spent are stored in strings. The program will
18~' standardize each string so that it is 9 characters long
19~' and includes two characters to the right of the decimal
2~~' point. This allows for input of variable length and an
2l~' optional decimal point.
22~ ,
23~' The various coordinates used in the program are found
24~' based on the following equations:
25~ ,
26~ , x = r * cos (theta)
27~ , Y = r * sin(theta)
28~ ,
29~' where x and yare the coordinates, r is the radius, and theta
3~~' is the angle. (Note: The y-coordinates are always multiplied
3l~' by ~.5. This is because the y pixels are twice the size of the
32~' x pixels.)
33~ ,
34~' If an angle theta is generated by a percent less than 1%, the
35~' section is not graphed, and the next theta is calculated.
36~ I However, the number will still be listed under the key.
37~ ,
38~ , Variables
39~' ACCT$(i) Description of the account
4~~' BUD$(i) Amount spent by the account
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