Beginning JAVA Programming CIS 175

1
Beginning JAVA Programming CIS 175

• File Input re Chapter 13
• Concepts from Chapter 3

2
Final

• Used for magic numbers
• Math.PI is pi
• Math.E is e
• Final variables are final they can not change.

3
Terminology

• parseDouble
• This is a Double class method
• Just like Math.pow is a Math class method
• Notice this is Double not double
• Double is called a wrapper class

4
parseDouble

• Converts a string into a double
• String s "8.0"
• double x
• x Double.parseDouble(s)

5
Reading from the keyboard

• Make a program more flexible
• Read a string, convert the string into a double
• Need System.in
• Need java.io.
• Need throws java.io.IOException
• Need InputStreamReader class
• Need BufferedReader class

6
Exception Handling

• See page 126
• Enclose program in a try block
• catch the errors
• Allows for removal of throws