Array's Loosing their values outside of the loop that assigned them.

[cuttsj]

I've been programming for 30+ years and this one has me stumped.

Here's the code: (The code in lower case is my debugging code.)

<...snip...>
      REAL SLOPE(100),CAREA(100)
      real slope2(100), carea2(100)
<...snip...>
C   FIND THE AVERAGE SLOPE IN EACH CONTOUR INTERVAL
C   FIND INDEX OF THE RIDGE LINE AND STORE IN KRIDGE
      KRIDGE=0
      write(6,9997)
9997  FORMAT(' I    II  Area           CArea(II)      Slope(II)     PerD
     +is       Elev(I)     Elev(II)')
      DO 100 I=2,NCTRS
      IF(ELEV(I-1).EQ.0.) KRIDGE=I-1
      IF(ELEV(I).EQ.0.) KRIDGE=I
      CALL INTRVL(NPTS,XCTR,YCTR,I,PERDIS,AREA,NCMAX,NPMAX,S1,S2,S3,
     $  1,NPTS(I-1),1,NPTS(I))
      II=I-1
      CAREA(II)=AREA
      SLOPE(II)=ABS(ELEV(I)-ELEV(II))/PERDIS
      carea2(ii)=area
      slope2(ii)=slope(ii)
      write(6,9999) i,ii,area,carea(ii),slope(ii),perdis,elev(i),
     +elev(ii)
  100 CONTINUE
      if (debug_flag) then
        write(6,9998)
9998  format('carea and slope output',/
     +' i    ii  carea(i)       carea2(i)      slope(i)      slope2(i)')
        do 5001 i=1,nctrs-1
          write(6,9999) i,i,carea(i),carea2(i),slope(i),slope2(i)
9999  format(2i4,6f13.4)
5001    continue
      endif
<...snip...>

The process is simple enough, work through a series of contours (XCTR, YCTR) and CALL INTRVL to return the AREA between the contours. Save the AREA in the CAREA() array and calculate the slope into the SLOPE() array. When I assign a value inside a loop and immediately print it back out I expect the get the same values back as were assigned. That's not what I'm getting. Here's my output:

I II Area CArea(II) Slope(II) PerDis Elev(I) Elev(II)
 2 1 25276.6875 25276.6875 37.8375 21.2488 804.0000 0.0000
 3 2 265195.9375 265195.9375 0.0103 193.8802 802.0000 804.0000
 4 3 255536.3594 255536.3594 0.0172 116.5833 800.0000 802.0000
 5 4 910855.3125 910855.3125 0.0056 357.2104 798.0000 800.0000
 6 5 1059779.5000 1059779.5000 0.0050 399.8702 796.0000 798.0000
 7 6 179444
3.0000 1794443.0000 0.0030 673.8806 794.0000 796.0000
 8 7 1186198.2500 1186198.2500 0.0043 461.6170 792.0000 794.0000
 9 8 1128319.8750 1128319.8750 0.0044 455.9271 790.0000 792.0000
 10 9 682406.4375 682406.4375 0.0069 291.9580 788.0000 790.0000
 11 10 169926.9375 169926.9375 0.0253 79.0579 786.0000 788.0000
 12 11 33344.5469 33344.5469 0.1160 17.2381 784.0000 786.0000
 13 12 67756.9375 67756.9375 0.0513 39.0164 782.0000 784.0000
 14 13 78870.6172 78870.6172 0.0404 49.5028 780.0000 782.0000
 15 14 73929.4531 73929.4531 0.0363 55.1556 778.0000 780.0000
 16 15 65075.1406 65075.1406 0.0311 64.2501 776.0000 778.0000
 17 16 46608.5625 46608.5625 0.0283 70.7828 774.0000 776.0000
 18 17 364544.0000 364544.0000 4.1337 186.0298 5.0000 774.0000
carea and slope output
i ii carea(i) carea2(i) slope(i) slope2(i)
 1 1 1273.5800 1772.1899 1568.2200 37.8375
 2 2 1277.0200 1773.1300 1568.3101 0.0103
 3 3 1279.9900 1773.4301 1567.9800 0.0172
 4 4 1282.4301 1773.1500 1567.2100 0.0056
 5 5 1284.3101 1772.3199 1566.1500 0.0050
 6 6&nb
sp; 1285.6801 1771.0400 1564.6600 0.0030
 7 7 1286.5800 1769.3500 1562.7200 0.0043
 8 8 1287.0699 1128319.8750 1560.3700 0.0044
 9 9 1287.5100 682406.4375 1557.6100 0.0069
 10 10 1288.3700 169926.9375 0.0253 0.0253
 11 11 1290.2100 33344.5469 0.1160 0.1160
 12 12 1291.4301 67756.9375 0.0513 0.0513
 13 13 78870.6172 78870.6172 0.0404 0.0404
 14 14 73929.4531 73929.4531 0.0363 0.0363
 15 15 65075.1406 65075.1406 0.0311 0.0311
 16 16 46608.5625 46608.5625 0.0283 0.0283
 17 17 364544.0000 364544.0000 4.1337 4.1337

As you can see, the values of CAREA are being overwritten by something somewhere somehow. The copy of the CAREA (CAREA2) is less damaged by the mysterious process and SLOPE2 ends up just fine. But I really need to know what's up with the data corruption in the CAREA and SLOPE arrays.

I hope this the result of a simple and boneheaded mistake on my part as those are easily fixed.

Thanks for your assistance.

[Steven_L_Intel1]

First, when you write out the values immediately after setting them, you ARE getting the same values. It's only at the end of the loop when you look again that the values change. My guess is that the call to INTRVL is corrupting the data due to mismatched argument declarations or out-of-bounds array references.

This is pretty easy to diagnose. Step through the loop in the debugger until one element of CAREA is set. Add a QuickWatch of that element in the debugger. Now step through the next iteration of the loop and into the call to INTRVL. Step line by line and watch the displayed value of the CAREA element to see when it changes.

You may also want to make sure that array bounds checking and interface checking are enabled.