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CSE110 Lecture 07

CSE110 Lecture 07

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

Javier Gonzalez-Sanchez
PRO

May 25, 2017
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  1. CSE110
    Principles of Programming
    with Java
    Lecture 07:
    Input and Formatted Output
    Javier Gonzalez-Sanchez
    [email protected]
    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
    [email protected]
    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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