Slides_MathClassAndWrapperClasses.pdf - Unit 2 Using...

Unit 2: Using Objects
Math And Wrapper Classes
Adapted from:
1) Building Java Programs: A Back to Basics Approach
by Stuart Reges and Marty Stepp
2) Runestone CSAwesome Curriculum

2
Static Methods
The Math class has many useful static methods. The class is part of the
java.lang package (group of classes) that is available by default(no need to
import to use). To call these, use the syntax:
Math. methodName ( parameters );
double answer = Math.sqrt(9.2);
int b = Math.round(5.6755);

3
Java's Math class
Method name Description
int abs(int x)
double abs(double x)
returns the absolute value of a int or double
value (overloaded method)
double pow(double base,
double exponent)
Returns the value of the first parameter raised
to the power of the second parameter
double sqrt(double x)
Returns the positive square root of a double
value
double random()
Returns a random double value greater than
or equal to 0.0 and less than 1.0
Constant Description
Math.E
2.7182818...
Math.PI
3.1415926...

4
Calling Math methods
• Examples:
double squareRoot = Math.sqrt(121.0) ;
System.out.println(squareRoot); // 11.0
int absoluteValue = Math.abs(-50) ;
System.out.println(absoluteValue); // 50
System.out.println( Math.min(3, 7) + 2); // 5
• The Math methods do not print to the console.