What I find confusing is this: If I am not mistaken the need for curly braces occurs when using more than one statement and if you use else statements.
So I wonder if I have missunderstood about the else statement and that you dont need curly braces around a one statement if statement that is followed by an else statement...
After i draw line between 2 fixed points on two different rectangles i need to rotate them. The problem is that my line is not updated, it stays on the same x1,y1 x2,y2. How to make line to follow rectangle when they are moving or rotating? I wrote some example code to demonstrate this.
Object that i want to draw:
[public class Object { private int xPos; private int yPos; private int width; private int height; float xDistance = 0f; float yDistance = 0f; double angleToTurn = 0.0;
At this moment in time my program compiles and runs as I want it to, but when I look at my code I see that my While Loops braces are placed inside my Try Block. When I move these braces outside of the Try Block, next to the WhileLoop, the program doesn't run like I want it to.
Likewise, when I place the While(answerIsCorrect) inside the Try Block, it doesn't work like I want it to either.
Also, my problem is on Lines 17 and 18.
import javax.swing.*; import java.util.Random; public class SwingInputExample { public static void main(String args[]) { int firstNumber=0; int secondNumber=0; int correctAnswer=0; String studentGuess = null;
I'm doing some revision for my OCAJ atm, & I came across this code in a mock question which takes two int arguments & simply returns the larger.
public int max(int x, int y){ if (x > y) return x; return y; }
When evaluating it I thought this would be invalid code as would always return x. But it transpires I was way off & that this actually works! In playing around with it, it seems like the first return statement is treated as:
if {// this bit } & the second return is treated as: else{ //this bit}.
What baffles me though is that you can put any amount of additional statements before the second return and it continues to work, however if you put even a single statement before the first return, the whole thing falls over.
I guess my two questions are - Am I right in my discovery above ( that statements preceeding the first return will always break it)? & secondly is this a good way of coding? for readability, I would always do it as:
public int max(int x, int y){ if (x > y){ return x; } else{ return y; } }
I just cant seem to understand the order of precedence here.
class Test{ public static void main(String[] args){ int k = 1; k += (k = 4) * (k + 2); System.out.println( k ); } }
From what I have read compound operators have the lowest order of precedence... But the above piece of code makes the assignment k = 1 + (k = 4) * (k + 2) before evaluating the rest of the statement first.
It then evaluates (k = 4) and proceeds with the remained of the statement 1 + 4 * (4 + 6)....
I dont understand why the first k is assigned 1 but the remaining ks 4. Should they not all be 1 or 4 (I would have thought 4, since += has the lost order of precedence so is evaluated last)??
I am working on the following java assignment..Write a program that randomly fills in 0s and 1s into a 4- by- 4 matrix, prints the matrix, and finds the first row and column with the most 1s. Here is a sample run of the program:
0011 0011 1101 1010
The largest row index: 2 The largest column index: 2
I have code that generates random 0s and 1s for the array, how to get the largest column and row.
import java.util.Random; public class LargestRowColumn { public static void main(String[] args){ //create 4x4 array matrix int arrayMatrix[][] = new int[4][4];
[code]....
finding the row and column with the largest amount of 1s. I keep thinking well if I scan and find a one in the array, maybe I can just save the index of the row and column and then determine which index contains the most 1's after the array has been scanned.
I would like to know what is the significance of instantiating an object without an assignment.
I have created a class TestClass1 with a single constructor that prints a test message.
In TestClass2, if I write "new TestClass1()" rather than "TestClass1 x = new TestClass1()" it still works, and prints the test message.
I would like to know if I do not assign an object at the time of instantiation, it cannot be referenced or reused later, then what is the significance of this type of construct and when it can be useful, and where is the object being held.
public class TestClass1 { TestClass1() { System.out.println("This is a test message"); } } public class TestClass2 {
I am trying to get items to display that would display in a command prompt now into a GUI. I am freaking lost at the moment, probably because I've been staring at this code for over a week now. I have included all the files that are necessary to run the program as an attachment for your own testing purposes. Should I be using a TextField to display the data from the CSV files? How do I get the data to be displayed? How would I get it to be displayed based on the different files Staples (newSTPL.csv), Apple (newAPPL.csv), and Microsoft (newMSFT.csv)?
Java Code:
import javax.swing.*; import java.awt.*; import java.awt.event.*; /** * DataAnalyzer Class * This class instantiates the methods from the ReadFiles Class and Calculations Class.
I have a 2 dimensional array assignment with a loop, i'm supposed find the average score of each student from a grade record and find the average score for each test. I've been trying to do the assignment all day with no progress. This is what i have so far
public class SiuTest { public static void main(String[] args) { String [] stu= new String [5]; int [] [] grade= new int [4][2]; String hold;
I have an assignment to create a Sphere class that will allow you to create Sphere objects using the code below. Then create a program called SphereTester that prompts the user for the radii of two spheres in meters. The program should display which sphere is larger and by how many cubic meters and display only four digits after the decimal point. I have the sphere class given to us for the assignment which is this:
public class Sphere { // instance variable (i.e., a field) private double radius; // constructor for the Sphere class public Sphere(double r) { radius = r;
[code]....
Here is a sample run of what the final result should look like
Enter the radius of a sphere (in meters): 1 Enter the radius of a 2nd sphere (in meters): 2 Sphere 2 is greater than Sphere 1 by 29.3215 cubic meters
I've been working on this same assignment using netbeans. I've completed the exercise and when I run it, it works. However, netbeans still had errors listed in the left hand numerical column and it asks me if I still want to run the program with errors when I hit run?
package TestScores; import java.util.Scanner; // Name: Joe // Date: ........ // Desc: Test Score Averages
[code].....
I found this thread while doing a google search trying to find out the error in my code.
So from what iv learnt in Java and programming in general is that using a case statement is far more efficient that using multiple IF statements. I have an multiple IF statements contained within a method of my program, and would like to instead use a case statement.
I thought numeric literal were by default int or doubles, depending on if have a . and numbers after the But I wrote a quick test program as listed below. I understand the float float floatA = 5.5; failed to compile since 5.5 is a literal of type double and you are trying to assign this to a floag
What I am having problems with is byte byteA = 5; 5 is a literal of type int and this is being assigned to a byte and compiler should complain.The compiler does not allow two byte values to be added and assigned to a byte since the result of the addition is an int
class literalTesting{ public static void main(String[] arg){ byte byteA = 5; // allowed WHY I thought literal is an int and assigning int to byte byte byteB = 10; // allowed
I understand the stack part of it, just not the loop, specifically how you give the user more than one option to input.
Implement a printer driver that handles incoming print jobs. The driver will behave in the following manner:
- Loop giving the user the following options: ADD print job, DELETE latest print job, and QUIT - Recording the following information from each job: computer name, document name, and number of pages - When the user chooses to ADD, add a new print job to the top of the stack - When the user chooses to DELETE, pop off the latest print job and output to the screen which job has just been deleted - When the user chooses to QUIT, output the print jobs still in the stack (in order from top to bottom) - Output must include all relevant information for each job.
Write a class encapsualting the concept of a course grade, assuming a course grade has the following attributes: a course name and a letter grade. Include a constructor, the accessor and mutator, and methods toString and equals.Write a client class to test all the methods in your class.
package labmodule7num57; import java.util.*; public class LabModule7Num57 { // Constructors//
URL....So the problem is that when I type in "PA" it will display about 24 Zips and Populations before it stops. The problem is in the ZIPs file. It goes down the list and then takes the Zip from the Zips file to the Zips in the Population file and displays the Population. It will go to population 513 and stop. Reason being, there is no ZIP code in the Population file to display a population. The loop then stops. How can I get the program to skip over the zip code when there is no corresponding ZIP code in the other file and continue showing the other Pops..Here's what I currently have completed:
import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; public class Population { //Declaring global variables. Scanner fileScannerZip, fileScannerPop, inputFile; private String lineZip, linePop; int invalidZip;
So I want to make a simple Java that ask the user to pick a powers and it has two options.If the user picks magic then execute the first if statement then ask the user again which type of magic the user wants.I can't make it work it keeps printing the else statement. Why is that?
import java.util.Scanner; public class Variable { static Scanner zcan = new Scanner(System.in); public static void main(String[] args)
