An if statement is NOT followed by a semicolon (i.e., `;`). If you wanna check whether `tower_height` is greater than or equal to `0` AND less than or equal to `23`. Then you probably need to write something like

    if (tower_height >= 0 && tower_height <= 23)
    {
        // do something
    }

Notice that you must repeat `tower_height` as it's regarded as a separate condition.

The code in the body of this if statement is executed *if and only if* both conditions are evaluated to true.

If an if statement doesn't have opening and closing curly braces, then only a single statement (specifically the one right after the statement) is executed when the condition is evaluated to true.