Accumulate Adding and Counting

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It mayu help is you look at these examples before you start. Using an Accumulator

Using an accumulator to add.

The variable list is an array, it holds several integers. For example it might be the list {1,2,3,4}.

You can iterate over a list, every time you visit an element of the list you do something to the accumulator acc

In this example, for every member v of the list you add that member to the accumulator using the code

acc = acc + v;


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Using an accumulator to count.

Use the accumulator to count the number of items in the list:


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Using an accumulator to multiply.

Use the accumulator to find the product of items in the list:


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Using an accumulator to max.

Use the accumulator to find the largest item in the list:


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Count Twos.

Use the accumulator to find the number of twos in the list: Count on a condition


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Count Non-Twos.

Use the accumulator to find number other than 2:

f({1,1,1,1})             -> 4
f({2,2,2})               -> 0
f({1,1,1,1,1})           -> 5
f({4,2,6,0,0})           -> 4


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Count the big numbers

Use the accumulator to count all numbers larger than 1:


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Add the big numbers

Use the accumulator to sum all numbers larger than 1:


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