C4.　イラストの作図

C4.3P1　プログラムリスト-1

10 DIM P[2,10]: REM reserve 10 points
20 REM draw polyline
30 DPERAS: DPWIND 0,-20,200
40 READ P: REM ========= Main loop
50 IF P[1,1]=9999 THEN GOTO 9010
60 NP=1: IOPEN=1
70 REM: ///loop-A/// to find number of points NP
80 IF P[1,NP+1]=9000 THEN GOTO 1000
90 IF P[1,NP+1]=9900 THEN GOTO 1010
100 NP=NP+1: IF NP>10 THEN GOTO 9000
110 GOTO 70 :REM /// return to loop-A 
120 REM ----------------------------------------
1000 IOPEN=0
1010 K=1
1020 DPMOVE P[1,1],P[2,1]
1030 DPDRAW P[1,K+1],P[2,K+1]
1040 K=K+1
1050 IF K<NP THEN GOTO 1030
1060 IF IOPEN=0 THEN GOTO 40
1070 DPDRAW P[1,1],P[2,1]: GOTO 40
9000 PRINT "data error"
9010 END