Conditionals

The conditional is if:

if (12 < 14) {
    20
} else {
    25
}

is 20.

Because of strict type checking the types of the two branches of the if must agree, and there must be an else branch. Also the curly braces are mandatory.

we also have else if:

if (a < 14) {
    20
} else if (a < 16) {
    22
} else {
    25
}

but the above is just syntactic sugar and is rewritten internally to:

if (a < 14) {
    20
} else {
    if (a < 16) {
        22
    } else {
        25
    }
}

if can act as an expression as well as a statement. The following is valid:

x = if (y > 2) { y } else { z };

Note the semicolon is required to terminate expressions.

There is also a switch expression, discussed later as it is just syntactic sugar.

Next: Variables