No — bugs are not allowed in restaurants, nor in programs.
All of the familiar mathematical functions
found on an electronic calculator such as
sine, log, and square root
are available in the Java Math
class.
Typically these functions expect data type double
as
a parameter and return a double
value.
Here is a program that reads a floating point number from the keyboard and prints out its square root:
import java.util.Scanner;
public class SquareRoot
{
public static void main (String[] args)
{
Scanner scan = new Scanner( System.in );
double value;
// read in a double
System.out.print ("Enter a double:");
value = scan.nextDouble();
// calculate its square root
double result = Math.sqrt( value );
// write out the result
System.out.println("square root: " + result );
}
}
The assignment statement (in blue) uses the sqrt()
method
of the class Math
.
This is a static method, which means that you ask for it using the
name of a class and a
dot operator, like this:
Class . method ( parameters )
This looks the same as calling a method of an object, but a class name is used, not an object name.
The class Math
also has a log
method that returns
the natural logarithm of its argument.
Mentally modify the program so that it returns the log of the input value.