CSE110 Lecture 07

Principles of Programming with Java
Input and Formatted Output
(202205)

Transcript

1. CSE110
   Principles of Programming
   with Java
   Lecture 07:
   Input and Formatted Output
   Javier Gonzalez-Sanchez
   javiergs@asu.edu
   javiergs.engineering.asu.edu | javiergs.com
   Office Hours: By appointment
   

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2. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 3
   Program
   MyProgram
   Java API
   (Application Programming Interface)
   Classes inside Packages = Files inside folders
   String
   Math
   System.out
   java.lang java.util java.net javax.swing
   

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3. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 4
   Java API Packages
   • The classes of the Java standard class library are
   organized into packages
   • java.lang
   • java.net
   java.util
   • java.awt
   • javax.swing
   • When you want to use a class from a package, you can
   import one class or all classes from the package into
   your program
   

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4. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 5
   Java API Packages
   • All classes of the java.lang package are imported
   automatically into all programs
   • Other classes should be explicitly imported. Examples:
   import javax.swing.JOptionPane;
   import javax.swing.*;
   

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5. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 6
   java.swing.JOptionPane
   

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6. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 7
   java.swing.JOptionPane
   

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7. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 8
   Parsing
   import javax.swing.JOptionPane;
   public class Lecture06 {
   public static void main(String [] args) {
   String test1= JOptionPane.showInputDialog(”write here:");
   int value1 = Integer.parseInt(test1);
   double value2 = Double.parseDouble(test1);
   System.out.println(value1);
   System.out.println(value2);
   }
   }
   

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8. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 9
   Integer.parseInt
   

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9. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 10
   Integer.parseInt
   

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10. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 11
    printf Method
    printf() method in System.out can be used to specify
    how many digits for a floating-point number should be
    display.
    Ex:
    double number = 1.0/3.0;
    System.out.printf("%.2f\n", number); //0.33
    System.out.printf("%7.3f\n", 89.123456789); //89.123
    

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11. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 12
    printf Method
    • %d à to print an integer
    • %5d à to print an integer with width 5
    • %7.2f à to print a floating point number with 2 digits
    after the decimal point and with width 7 (including
    the decimal point)
    • %s à to print a string
    

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12. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 13
    Example
    String str = "apples";
    int num = 5;
    double price = 3.477;
    System.out.printf("%d %s cost $%.2f\n", num, str, price);
    //The above prints:
    //5 apples cost $3.48
    

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13. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 14
    Reference
    Textbook – Pages 57 and 328
    

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14. CSE110 - Principles of Programming
    Javier Gonzalez-Sanchez
    javiergs@asu.edu
    Summer 2022
    Disclaimer. These slides can only be used as study material for the class CSE110 at ASU. They cannot be distributed or used for another purpose.
    

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