Accumulate over a File

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You may find the page on accumulating variables useful:

How many countries in Asia?

In this example we use an accumulator to count the countries in Africa.

Notice that acc shows up three times:

  • The accumulator acc is set to zero at the start.
  • Every time we encounter Africa we increment acc.
  • After the loop has completed acc contains the value we want - so we print it.

Change the program so that it counts the countries of Asia.


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How many big countries?

Count the number of countries with an area of more than 1500000.

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Numbering countries.

Produce a numbered list of countries:

  1 Afghanistan
  2 Albania
  3 Algeria
...
262 Zimbabwe

Use three character spaces for the number and put a single space after it.

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Country number 42.

Print the name of country number 42

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Total area

Calculate the total area of the world.

This time we add to the accumulator each time. We can use either of the statements below:

acc = acc + area;
acc += area;

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Total population

Calculate the total population of the world.

The answer - at a little over 6 billion will be too large for an int. Use a long instead.

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Total GDP of Africa

Calculate the total GDP of the countries of Africa.

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Total GDP of the 'West'.

Calculate the total GDP of the western world. Include the regions "North America", "Europe" and "Oceania" as the western world.

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