awk doesn't understand 'read' statement!!! Post: 302796867

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Top Forums Shell Programming and Scripting awk doesn't understand 'read' statement!!! Post 302796867 by hanson44 on Sunday 21st of April 2013 04:31:29 AM

04-21-2013

Registered User

Quote:

I thought that if user input is not to be used, then
the code doesn't need continue or break. If possible, may I
expect anyone to give a small algorithm or example to show
how without user input, 'continue/break' makes sense.

Here are a few continue and break examples from source code:

Code:

  for (absNdx_NotAtom = 0; absNdx_NotAtom < absNdx1_Atom; absNdx_NotAtom++) {
    pckNdx = RWV_GEO_Abs_PckNdx___Array_g [absNdx_NotAtom];
    if (pckNdx < 0) {
      continue; // NOT picked
      }
    /* Many additional processing steps */
    }

Code:

    for (rowNdx = 0; rowNdx < rowCntOmitSum; rowNdx++) { // Do sum
      if (possiblySkipRow_IfAgeAdjustTicVar == TRUE) {
        if (RowVarNdx_EvtArrays_g == cryVarNdx_Age) {
          if (i64Array == RWA_I64_Pop_Denom________g) {
            if (OmitRowFromPopTotals_g [rowNdx] == TRUE) {
              continue;
              }
            }
          }
        }
      /* Many additional processing steps */
      }

Code:

  while (1 == 1) {
    eightBitNumber = (int) (numberToUse % 128);
    numberToUse /= 128;
    if (numberToUse > 0) {
      eightBitNumber |= 0X80;
      }
    binaryDataArray [0] = eightBitNumber;
    fwrite (binaryDataArray, 1, 1, binWtr);
    if (numberToUse == 0) {
      break;
      }
    }

Code:

  while (1 == 1) {
    items = fread (binaryDataArray, 1, 1, binRdr);
    eightBitNumber = binaryDataArray [0];
    sevenBitNumber = eightBitNumber & 0X7F;
    intRead += (sevenBitNumber * factorUsed);
    factorUsed *= 128;
    if ((eightBitNumber & 0X80) == 0) {
      break;
      }
    }

The isolated examples probably mean little or nothing to you. The point is programmers use break and continue all the time in situations not processing user input.

Here is a simple example using bash, showing how break and continue make sense:

Code:

while read field_1 field_2; do
  if [ $field_1 = "skip_me" ]; then
    continue
  fi
  if [ $field_1 = "bail_out" ]; then
    break
  fi
done

You are right that break and continue are often useful for processing user input. But there are obviously many kinds of input. Input from data files. Input from arrays. Input from strings. Input from numbers. Perhaps other inputs. Those other inputs also have to be read in some way, and break / continue are helpful for processing those other inputs too. There is no "special connection" between reading user input and continue/break.

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