The value of a constant cannot change through re-assignment, and a constant cannot be re-declared. Because of this, although it is possible to declare a constant without initializing it, it would be useless to do so.
The Number() function converts the object argument to a number that represents the object’s value. If the value cannot be converted to a legal number, NaN is returned. Note: If the parameter is a Date object, the Number() function returns the number of milliseconds since midnight January 1, 1970 UTC.
How do you declare a number?
To declare (create) a variable, you will specify the type, leave at least one space, then the name for the variable and end the line with a semicolon ( ; ). Java uses the keyword int for integer, double for a floating point number (a double precision number), and boolean for a Boolean value (true or false).
isNaN() method determines whether a value is NaN (Not-A-Number). This method returns true if the value is of the type Number, and equates to NaN. Otherwise it returns false. … isNaN() does not convert the values to a Number, and will not return true for any value that is not of the type Number.
What is difference between declaration and initialization?
Declaration tells the compiler about the existence of an entity in the program and its location. When you declare a variable, you should also initialize it. Initialization is the process of assigning a value to the Variable. … If the value is not assigned to the Variable, then the process is only called a Declaration.
1+ +”2″+3 results 6 1+”2″+3 results “123” AS The unary + operator converts its operand to Number type. +”2″ is a way to cast the string “2” to the number 2 . The remain is a simple addition.
What will happen if you use the variable without initializing it?
Notice that a variable that is not initialized does not have a defined value, hence it cannot be used until it is assigned such a value. … The variable line is not initialized before we request to print it (the error is detected at compile time).
What is && mean?
The && (logical AND) operator indicates whether both operands are true. If both operands have nonzero values, the result has the value 1 . Otherwise, the result has the value 0 .