How to use an accumulating variable

From Progzoo

When using an accumulating variable there are three stages:

Initialise

We declare our accumulator and set it to an initial values.

Update

Inside the loop we update the accumulator - we take into account the current data item.

Output/use

After the loop our accumulator contains the required value. We use it or output it.

Contents

Using an accumulator to add.

  • We initialise to 0.
  • We add to the accumulator.
  • The value printed is the sum 0+2+7+1+1.
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Using an accumulator to count.

  • We initialise to 0.
  • We increment the accumulator.
  • The value printed is the count: 0+1+1+1+1.
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Using an accumulator to multiply.

  • We initialise to 1.
  • We multiply the accumulator.
  • The value printed is the product: 1*2*7*1*1
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Using an accumulator to find the maximum.

  • We initialise to 0.
  • We take the max.
  • The value printed is the largest:
max(max(max(max(0,2),7),1),1)
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Using an accumulator to concatenate.

  • We initialise to "".
  • We concatenate the next value.
  • Each time i gets converted to a string and is put at the end.
  • The answer is ""+2+7+1+1
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Using two accumulators to find the mean.

  • We initialise both to 0.
  • We add to the sum and increment the count.
  • We divide the sum by the count to get the average.
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Using an accumulator to calculate.

  • We initialise to 0.
  • We multiply by the radix and add the next digit.
  • By the end the number 2 has been multiplied by 10 three times,

the number has been multiplied by 10 twice...

  • 10*(10*(10*2+7)+1)+1
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