20172319 2018.04.11 "Java Programming Tutorial" 7th Week class Quiz (write-up blog)

20172319 2018.04.11 "Java Programming Tutorial" 7th Week Classroom Quiz

• Program: Program design and data structure
  
• Class: 1723
• Student: Tang Caiming
• Study No.: 20172319
• Instructor: Wang Zhiqiang
• Date: 2018.04.11
• Compulsory/elective: compulsory

Directory

• Test content
• Test requirements
• Experimental steps
  
• • Pre-preparation
• • Demand analysis
• Code implementation and interpretation
• Program run results and code
• Testing process and problems encountered
• Resources

Test content

• Complete the Programming Project PP7.4: Specific reference to the Java Programming Tutorial (eighth edition)
• Implementation of the Compareble interface

Test requirements

• Compile and run the project PP7.4; and (class code, test code, run result code) send to blue ink cloud
• Managed code to [email protected], detail reference using open source China managed code
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Preliminary preparation of the experimental procedure

• Knock on the textbook example 7.3 (rationaltester2.java-test) and Example 7.4 (rationalnumber2.java-Class), compile and run to see if it is wrong, if wrong, control the textbook to two code one after the troubleshooting, you can start programming project.

Demand analysis

1. Need to understand the basics of interfaces
2. Learn how to implement interfaces
3. Understand the comparable interface and the CompareTo method it contains (the only method)

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Code implementation and interpretation

The class that implements the interface for the
1. is to use the reserved word implements on the class declaration head, followed by the interface name. Add implements COMPARABLE<RATIONALNUMBER2> to the end of the head of the Rationalnumber class; declares that you want to implement the comparable interface.
   public class RationalNumber2 implements COMPARABLE<RATIONALNUMBER2>
2. if a class declares to implement an interface, it must provide implementation code that implements all the methods in the interface. Therefore, to implement the interface completely requires code in the RationalNumber2 class that implements all the methods in the interface. public int CompareTo (RationalNumber2 op2)
The

3. Converts the value of the object in the RationalNumber2 to a floating-point value, and then compares it with a defined error standard (reason: a good way to refer to a floating-point numerical comparison in WEEK5 learning summary).

     Double n1, N2, difference;  N1 = (double) numerator/denominator;  N2 = (double) op2.getnumerator ()/Op2.getdenominator ();  difference = Math.Abs (N2-N1);  if (Difference < 0.0001) return-1;     else if (Difference > 0.0001) return 1;
    else return 0;  

4. Test program code

public class rationaltester2{//----------------------------------------------------------------------//Creates   Some rational number objects and performs various//operations on them.      ----------------------------------------------------------------------public static void Main (string[] args) {      RationalNumber2 r1 = new RationalNumber2 (1, 3);      RationalNumber2 r2 = new RationalNumber2 (1, 9);      RationalNumber2 R3, R4, R5, R6, R7;      System.out.println ("First rational Number:" + R1);      System.out.println ("Second Rational Number:" + R2);      if (R1.islike (R2)) System.out.println ("R1 and R2 are equal.");      Else System.out.println ("R1 and R2 is not equal.");        if (R1.compareto (r2) = = 1) System.out.println ("R1 > R2");        else if (R1.compareto (R2) ==-1) System.out.println ("R1 < R2");      Else System.out.println ("r1 = R2");      R3 = R1.reciprocal (); System.out.println("The reciprocal of R1 is:" + R3);      R4 = R1.add (R2);      R5 = R1.subtract (R2);      R6 = r1.multiply (R2);      R7 = r1.divide (R2);      System.out.println ("R1 + R2:" + R4);      System.out.println ("R1-R2:" + R5);      SYSTEM.OUT.PRINTLN ("R1 * R2:" + R6);   System.out.println ("R1/R2:" + R7); }}

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Program run results and code

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Testing process and problems encountered

• Issue 1: The unknown of the conditional statement and the incorrect use of the relational operator result in an output error.
• Solution: Learn the conditional statements, then debug the code, find the unreasonable place to modify.
• Question 2: The knowledge of class writing is still vague and unclear, which leads to the obstruction of the initial programming work.
• Solution: Find data, in the class carefully analyze the role of each statement, define the appropriate method name for easy invocation.
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Resources

• Java Programming and Data Structure Tutorial (second edition)
• Tutorial on Java Programming and data Structure (second edition) Learning Guide
• Construction method, toString (), this, return
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20172319 2018.04.11 "Java Programming Tutorial" 7th Week class Quiz (write-up blog)