In any imperative programming language, an expression is a line or fragment of code that is computed to produce a value whereas statement is a standalone unit of the program which intends to perform some action. In languages like C# or Java, we have control structures for decision making , branching etc.. as statements rather than expressions.
The following snippet shows a classic “If -Else” statement in C#.
However, this can be simplified and curly braces are not mandatory here.
But I cannot write the following in C#. This is because I cannot return a statement where a function is supposed to return an “int”.
Similar stuff can be done in C# with a ternary operator as shown below:
But as the conditional statement becomes complex, usage of a ternary operator is difficult and makes the code clumsy and kludgy.
While playing around with Kotlin, I found that control structures like “If” , “When ( switch in C# or Java)” are expressions instead of statements and evaluates to a value. So, I can easily write the following.
This works as a simple alternative to the ternary operator. In Kotlin, there is no ternary operator as we don’t need any. But if-else expressions can be complex with multiple expressions/statements within it.In that case the last expression will be the “value” of that parent if/else expression as shown below.
Nested If-Else, If-Else-If expressions will also work in the same logic.
Kotlin, also has statement blocks enclosed within curly braces and the following “If” block without an “Else” is treated as a statement.
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