if expressions

You use if expressions exactly like if statements in other languages:

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In addition, you can use if as an expression. The last expression of each block becomes the value of the if expression:

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Speaker Notes

This slide should take about 4 minutes.

Because if is an expression and must have a particular type, both of its branch blocks must have the same type. Show what happens if you add ; after "small" in the second example.

An if expression should be used in the same way as the other expressions. For example, when it is used in a let statement, the statement must be terminated with a ; as well. Remove the ; before println! to see the compiler error.