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Java

Katie Diamond
Katie Diamond
2,035 Points
Posted by Katie Diamond
Katie Diamond
2,035 Points

What are the "$"s in "$3" and "$4" in this video (Welcome Back with Craig Dennis) about Java basics?

In this video, there are instances of variables being returned as something like:

$3 ==> true $4 ==> false $5 ==> 40

What does the "$3" mean, for example? Where are these variable coming from? I googled it and it sounded like a dollar sign meant an error, but these clearly are not errors.

Thanks so much! Katie

1 Answer

jb30
jb30
44,806 Points
jb30
jb30
44,806 Points

When the output of an expression is not explicitly assigned to a variable, JShell creates a variable of the form $ followed by an integer to refer to the output so that the output can be used later. For example, boolean b = $3 && !$4 will explicitly assign the value true to the variable b since $3 was assigned to be true and $4 was assigned to be false. If instead you used $3 && !$4 by itself, JShell will create a new variable $6 with a value true.