replace arithmetic gotos; now compiles without warnings

1 files changed, 32 insertions, 17 deletions

diff --git a/htdp.f b/htdp.f
index 1ed5b2c..7c4724b 100644
--- a/htdp.f
+++ b/htdp.f
@@ -334,8 +334,9 @@ C
 C     FIND STARTING POINT WHERE X(I).NE.X0
       IP=0
    10 IP=IP+1
-      IF(X(IP)-X0) 15,12,16
-   12 IF(IP.LE.N) GO TO 10
+      IF (X(IP) .lt. X0) goto 15
+      if (X(IP) .gt. X0) goto 16
+      IF(IP.LE.N) GO TO 10
       WRITE(LUOUT,6001)
  6001 FORMAT('0  POLYGON INPUT ERROR - ALL POINTS ON LINE X = X0')
       STOP
@@ -352,30 +353,44 @@ C
       DO 100 II=IP1,IPN
       I=II
       IF(I.GT.N) I=I-N
-      IF(IL) 30,50,40
-   30 IF(X(I)-X0) 90,32,34
-   32 IS=-1
+      if (IL .eq. 0) goto 50
+      if (IL .gt. 0) goto 40
+      IF (X(I) .lt. X0) goto 90
+      if (X(I) .gt. X0) goto 34
+      IS=-1
       GO TO 60
    34 IL=1
       GO TO 80
-   40 IF(X(I)-X0) 42,44,90
-   42 IL=-1
+   40 IF(X(I) .eq. X0) goto 44
+      if(X(I) .gt. X0) goto 90
+      IL=-1
       GO TO 80
    44 IS=1
       GO TO 60
-   50 IF(X(I)-X0) 52,55,54
-   52 IL=-1
-      IF(IS) 90,140,80
+   50 IF(X(I) .eq. X0) goto 55
+      if(X(I) .gt. X0) goto 54
+      IL=-1
+      IF (IS .lt. 0) goto 90
+      if (IS .eq. 0) goto 140
+      goto 80
    54 IL=1
-      IF(IS) 80,140,90
-   55 IF(Y(I)-Y0) 57,120,58
-   57 IF(YL-Y0) 90,120,120
-   58 IF(YL-Y0) 120,120,90
+      IF(IS .lt. 0) goto 80
+      if(IS .eq. 0) goto 140
+      goto 90
+   55 IF(Y(I) .eq. Y0) goto 120
+      if(Y(I) .gt. Y0) goto 58
+      IF(YL .ge. Y0) goto 120
+      goto 90
+   58 IF(YL .le. Y0) goto 120
+      goto 90
 C
    60 IL=0
-      IF(Y(I)-Y0) 90,120,90
-   80 IF(YL-Y0+(Y(I)-YL)*(X0-XL)/(X(I)-XL)) 90,120,85
-   85 NPC=NPC+1
+      IF (Y(I) .eq. Y0) goto 120
+      goto 90
+   80 tmp = YL-Y0+(Y(I)-YL)*(X0-XL)/(X(I)-XL)
+      IF (tmp .lt. 0) goto 90
+      if (tmp .eq. 0) goto 120
+      NPC=NPC+1
    90 XL=X(I)
       YL=Y(I)
   100 CONTINUE