'===========================================================================
' Subject: GEOMETRY OF A CIRCLE              Date: 11-05-96               
' Author:  Steven A. Morisi                  Code: QB, QBasic, PDS        
' Origin:  steve179@ix.netcom.com          Packet: GRAPHICS.ABC
'===========================================================================
DECLARE SUB define5 ()
DECLARE SUB define3 ()
DECLARE SUB define4 ()
DECLARE SUB define1 ()
DECLARE SUB define2 ()
DECLARE SUB circinit ()
DECLARE SUB header1 ()
DECLARE SUB choices ()

'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
'  Geometry Definitions for Circles
'  Author : Steven A, Morisi
'  Date   : 10/96
'  Notes  : E-Mail with comments to steve179@netcom.com
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
CLS
SCREEN 9
COLOR 7, 1
WIDTH 80, 43     'give myself more room
    header1      'print header
    circinit     'print initial circle
    choices      'Display choices


DO
     DO
          key.press$ = INKEY$
     LOOP WHILE key.press$ = ""

'     PRINT key.press$
     SELECT CASE UCASE$(key.press$)
            CASE IS = "D"
                 CLS
                 choices
                 header1
                 circinit
                 LINE (308, 165)-(548, 165), 9
                 define1
            CASE IS = "R"
                 CLS
                 choices
                 header1
                 circinit
                 LINE (308, 165)-(428, 165), 9
                 define2
            CASE IS = "C"
                 CLS
                 choices
                 header1
                 circinit
                 CIRCLE (428, 165), 120, 9
                 define3
            CASE IS = "H"
                 CLS
                 choices
                 header1
                 circinit
                 LINE (309, 170)-(505, 100), 9
                 define4
            CASE IS = "T"
                 CLS
                 choices
                 header1
                 circinit
                 LINE (300, 102)-(480, 60), 9
                 define5

            CASE IS = CHR$(27)
                 EXIT DO
     END SELECT
LOOP
SYSTEM

SUB choices
FOR i% = 0 TO 3 STEP 3
    LINE (50 - i%, 55 - i%)-(205 + i%, 200 + i%), 5, B
NEXT i%
LOCATE 9, 8: PRINT " Press a letter   "
LOCATE 11, 8: PRINT " (D)iameter      "
LOCATE 13, 8: PRINT " (R)adius        "
LOCATE 15, 8: PRINT " (C)ircumference "
LOCATE 17, 8: PRINT " c(H)ord         "
LOCATE 19, 8: PRINT " (T)angent       "
LOCATE 23, 8: PRINT " Escape : Quit   "
END SUB

SUB circinit
    
     CIRCLE (428, 165), 120, 2
     PSET (428, 165), 4

END SUB

SUB define1
'Diameter definition
'SOUND 600, 4
LINE (50, 285)-(590, 305), 3, BF
LOCATE 37, 8
PRINT " The diameter is any line that starts somewhere on the circle,    "
LOCATE 38, 8
PRINT " goes through the center and touches the circle on the other side."
END SUB

SUB define2
'Radius definition
'SOUND 700, 4
LINE (50, 285)-(590, 305), 3, BF
LOCATE 37, 8
PRINT " The Radius is any line that starts at the center and goes to the "
LOCATE 38, 8
PRINT " edge of the circle. It is 1/2 the diameter.                      "

END SUB

SUB define3
'Circumference definition
'SOUND 600, 4
LINE (50, 285)-(590, 305), 3, BF
LOCATE 37, 8
PRINT " The Circumference is the distance around the circle. You can     "
LOCATE 38, 8
PRINT " calculate the circumference by multiplying the diameter x pi.    "

END SUB

SUB define4
'chord definition
'SOUND 600, 4
LINE (50, 285)-(590, 305), 3, BF
LOCATE 37, 8
PRINT " A chord is a line that touches a circle in 2 places. The diameter"
LOCATE 38, 8
PRINT " is the largest chord of a circle.                                "

END SUB

SUB define5
'tangent definition
'SOUND 600, 4
LINE (50, 285)-(590, 305), 3, BF
LOCATE 37, 8
PRINT " A TANGENT is a line that touches a circle in ONLY 1 place.       "
LOCATE 38, 8
PRINT "                                                                  "
END SUB

SUB header1
'    Draw box in which to display circle
     LINE (275, 50)-(590, 275), 15, BF
'    Title on Box                                                                                                     
     LOCATE 5, 47: PRINT " CIRCLE FACTS "

END SUB