This program illustrates the "unusual" behavior of m[kVal] when the map m does
not contain a key equal to kVal. If the map does contain a component with key
value kVal, this expression gives us the value from the corresponding key/value
pair. If it does not contain this key, then a new component is inserted into
the map. The new component has the given key, and the corresponding value is
the default value of the value type (VType) of the pairs in the map m.
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First we create an empty map and put three numbered greetings into it.
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Next we display those greetings.
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Here is greeting 1: Hello!
Here is greeting 2: How's it goin'?
Here is greeting 3: Hey! Whatcha been up to?
Current size of map = 3
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And now for the big surprise ...
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Wait for it ...
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Even though we did not enter this greeting ...
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Here is greeting 4: Hi there!
And now ... size of map = 4
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