CSE110 Lecture 11

Principles of Programming with Java
Review
(202005)

Transcript

1. CSE110
   Principles of Programming
   with Java
   Lecture 11:
   Review
   Javier Gonzalez-Sanchez
   javiergs@asu.edu
   javiergs.engineering.asu.edu | javiergs.com
   Office Hours: By appointment
   

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2. Note about Strings
   

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3. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 3
   Comparing Strings
   • Remember that a character string in Java is not a
   primitive data type.
   • We cannot use the relational operators to compare
   strings
   • Do NOT do this
   String str1 = "apple";
   String str2 = "banana";
   if (str1 == str2){//we are not supposed to do this
   }
   

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4. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 4
   Comparing Strings
   String str1 = "apple";
   String str2 = "banana";
   //do NOT do this
   if (str1 == str2){
   }
   // Instead we need to do:
   if (str1.equals(str2)){
   }
   

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5. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 5
   Comparing Strings
   • The following does not also compare two strings:
   String str1 = "apple";
   String str2 = "banana";
   //do NOT do this
   if (str1 < str2){
   }
   // Instead we need to do:
   if (str1.compareTo(str2) < 0){
   }
   

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6. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 6
   Example
   int result = str1.compareTo(str2);
   if (result < 0) {
   //if str1 is smaller than str2
   } else if (result > 0){
   //if str1 is larger than str2
   } else if (result == 0)
   //if str1 is identical to str2
   }
   

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7. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 7
   Comparing Strings
   • Comparing strings is based on a character set, it is
   called a lexicographic ordering
   • It uses Unicode of each character in strings.
   • Also, short strings come before longer strings with
   the same prefix (lexicographically)
   Therefore "book" comes before "bookcase"
   

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8. Midterm Exam 1
   

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9. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 9
   Lectures
   

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10. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 10
    Disclaimer
    The previous questions are just examples.
    They are NOT a comprehensive list of topics
    Review All the Slides for a full list of topics
    The exam is NOT limited to the topics covered in the previous
    questions. For instance printf() was not in the previous
    examples; but could be part of your exam
    

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11. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 11
    Day 2
    1. What is a compiler?
    2. What is Java byte code?
    3. Give an example of a lexical error in Java
    4. Give an example of a syntactic error in Java
    5. Give an example of a semantic error in Java
    

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12. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 12
    Day 3
    1. What is a variable?
    2. What is a method?
    3. What is a class?
    4. Create a program that prints “This is my exam”.
    Including the code for creating a class and main
    method.
    5. Write 3 reserved words in Java
    

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13. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 13
    Day 4
    1. Write a multi-line comment with your name and
    ASUID
    2. Mention the 8 primitive types defined in Java
    3. Is the following statement correct?
    char = ' ' ';
    4. Is the following statement correct?
    boolean result = 5 + 2 > 5 - 1 ;
    5. What is the result of (-20 % 3 -2)
    

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14. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 14
    Day 5, 6
    1. What is the result of 1 % 2 - 3 / 4 * 5 / 6 + 7
    2. Is the following correct? If so, What is the result?
    1 % 2 - 3 / 4 * 5 / 6 + 7 + “Hello”
    3. Is the following correct? If so, What is the result?
    ”Hello” + 1 % 2 - 3 / 4 * 5 / 6 + 7
    4. Is the following correct? If so, What is the result?
    float f = 2.5f + 2.5f; System.out.println(f);
    5. Is the following correct? If so, What is the result?
    System.out.println( Math.pow(5.0,2.0) );
    

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15. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 15
    Solution
    

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16. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 16
    Day 7
    1. What is a package?
    2. What is the next instruction for?
    JOptionPane.showInputDialog(“this is a message”);
    3. What is the next instruction for?
    Integer.parseInt(“12345”);
    4. What is JOptionPane?
    5. What is showInputDialog?
    

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17. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 17
    Day 8, 9
    int x = 75; y = 95; z = 1;
    if (x < y && x < z) {
    if (y < z)
    System.out.println( x + " " + y + " " + z );
    else
    System.out.println( x + " " + z + " " + y );
    } else if (x > y && x > z) {
    if (y < z)
    System.out.println( y + " " + z + " " + x );
    else
    System.out.println( z + " " + y + " " + x );
    } else {
    if (y < z)
    System.out.println( y + " " + x + " " + z);
    else
    System.out.println( z + " " + x + " " + y);
    }
    

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18. Javier Gonzalez-Sanchez | CSE110 | Summer 2020 | 18
    Day 10
    public class Example {
    public static void main(String args[]) {
    int age = 18;
    switch (age) {
    case 16:
    System.out.println("You are under 18.");
    break;
    case (18):
    System.out.println("You are eligible for vote.");
    break;
    case (65):
    System.out.println("You are senior citizen.");
    break;
    default:
    System.out.println("Please give the valid age.");
    break;
    }
    }
    }
    

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19. CSE110 - Principles of Programming
    Javier Gonzalez-Sanchez
    javiergs@asu.edu
    Summer 2020
    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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