Can you compare a variable to see if it's greater than and less than a value, without listing the variable twice?

Question

if (age > 18 && age < 21) {
return true;
}

if (age < 18 && > 21) ???

Answer 1

Try this.

static boolean inrange(int age) {
    return Math.abs(age - 19.5) < 1.5;
}

public static void main(String[] args) {
    for (int i = 15; i < 25; ++i)
        System.out.println(i + " " + inrange(i));
}

output:

15 false
16 false
17 false
18 false
19 true
20 true
21 false
22 false
23 false
24 false

Or

static boolean inrange(int age) {
    switch (age) {
    case 19: case 20: return true;
    default: return false;
    }
}

Answer 2

No, on each side or the || is a new statement. The compiler or interpreter will not know how to parse it. For example, what happens if you want if (age > 18 && height < 5) ? The Java interpreter does not know what you want and assumes it is a mistake if the second variable is missing.

In some cases, you can use a ternary operator but this is not what you want.