100 REM Angle difference between two bearings
110 DECLARE EXTERNAL FUNCTION GetDiff
120 REM
130 SUB PrintRow(B1, B2)
140    PRINT USING "#######.######    #######.######    #######.######": B1, B2, GetDiff(B1, B2)
150 END SUB
160 REM
170 print "Input in -180 to +180 range"
180 PRINT "     Bearing 1         Bearing 2        Difference"
190 CALL PrintRow(20.0, 45.0)
200 CALL PrintRow(-45.0, 45.0)
210 CALL PrintRow(-85.0, 90.0)
220 CALL PrintRow(-95.0, 90.0)
230 CALL PrintRow(-45.0, 125.0)
240 CALL PrintRow(-45.0, 145.0)
250 CALL PrintRow(-45.0, 125.0)
260 CALL PrintRow(-45.0, 145.0)
270 CALL PrintRow(29.4803, -88.6381)
280 CALL PrintRow(-78.3251, -159.036)
290 PRINT
300 PRINT "Input in wider range"
310 PRINT "     Bearing 1         Bearing 2        Difference"
320 CALL PrintRow(-70099.74233810938, 29840.67437876723)
330 CALL PrintRow(-165313.6666297357, 33693.9894517456)
340 CALL PrintRow(1174.8380510598456, -154146.66490124757)
350 CALL PrintRow(60175.77306795546, 42213.07192354373)
360 END
370 REM
380 EXTERNAL FUNCTION GetDiff (B1, B2)
390 LET R = MOD(B2 - B1, 360.0)
400 IF R >= 180.0 THEN LET R = R - 360.0
410 LET GetDiff = R
420 END FUNCTION