How To Type Bitwise Operator Symbol
Jul 6, 2014It looks like an upside down v , i cant find it on my keyboard. I assume its a keyboard combo.
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Tester Class - Create Objects Of New Type And Then Use Dot Operator
Jun 12, 2014So I'm beginning to learn java with the book HeadFirst Java. The books says that all a tester class does is create objects of a new type and then use the dot operator...
I don't really understand what a tester class is and what it does ? and what is the Dot operator and how does it work ?
Rotate Left Bitwise Shift?
May 13, 2014I'm trying to replicate the rol(rotate left) instruction in assembly though can only get as far as shifting the bits with '<<' or doing Long.rotateLeft(var, 5). Both of these method don't wrap around the bits as the rol instruction does.
View Replies View RelatedCompound Assignment Operator
Jan 8, 2014I 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)??
Difference Between Operator And Method
Jun 4, 2014I know instanceof is an operator and println is a method. But what is the difference between the two? How are they different/same?
View Replies View RelatedOperator In Case Of Strings
May 23, 2015After the executing the code below:-
class Test
{
public static void main(String [] args)
{
String s = new String("new") ;
String d = new String("new") ;
System.out.println((s==d)+ " "+s.equals(d)) ;
System.out.println(s==d + " "+ s.equals(d)) ;
}
}
OUTPUT:- false true
false
Why did the output change in the second print statement?
Why Operator Overloading Is Not Supported In Java
Oct 18, 2014why operator overloading is not supported in Java.
View Replies View RelatedUsing Values That Are Set For Cases In The Switch Operator
Mar 23, 2014I am new to Java and I am trying to use values that are set for cases in the switch operator.
The first menu ask for you to pick a product and each product has a price on it.
The second menu ask you to pick a state with each state having a decimal value on it.
The third is asking you to put the number of cases and each case is 12 items.
A key note to remember is that each part that a person is choosing is on a different instance!
Here is an example of what i am trying to do.
Menu 1: I picked case 1 that is Computer and it is worth 1000
Menu 2: I picked case 1 that is CT and it's tax is 7.5
Third choice: I picked case 1 and that has 12 items
I want the subtotal witch is: (1000 * 12)
Subtotal in this situation is: 120000
Next i need the total value which is based on what state they picked for the tax percent value picked from the state menu case: (12000 * 0.075 + 120000)
Total value is: 129000
I will post the code I have but based on the choices a person makes will determine the values and I need those values set in the cases to put in a math equation. The problem I am having is retrieving these numbers form the cases inside the menu options and they are on a different instance. So How can I do this in Java code?
Here is the code:
This is menu 1
Java Code:
import java.util.*; //scanners and more
class menu{
public void display_menu() {
System.out.println ("Please select your product"); //Gives user direction
System.out.println ( "1)
[Code] .....
Program Ask For Operator And Two Numbers And Do Math
Feb 17, 2015This program is supposed to ask for the operator (+ or -) then ask you for two numbers and do the math. When I run it it comes up- Enter operator. When I say add or sub nothing happens. Here it is:
import java.util.Scanner;
public class Echo1{
public static void main(String args[]){
Scanner userInput = new Scanner(System.in);
System.out.println("Enter Operator");
String operator = userInput.next();
[Code] ....
HashMaps / ArrayLists - Diamond Operator?
Jul 8, 2014So I am learning HashMaps/Arraylists and I can't really understand the diamond operator or what it's for. Take the following code for example: Why could we not just do this without the diamond?
Java Code:
import java.util.HashMap;
class Untitled {
public static void main(String[] args) {
HashMap<String, String> map = new HashMap<String, String>();
map.put("California","Sacramento");
map.put("Oregon","Salem");
map.put("Washington","Olympia");
System.out.println(map);
}
} mh_sh_highlight_all('java');
Bad Operand Types For Addition Operator
Apr 25, 2015I would like to know that i am getting an error with the random. it is say bad operand types for binary operator ' +'
[/ Random generator = new Random(15) + 1];
And And Or Operator - Manipulate Bits In A Variable
Jun 1, 2014I am trying to understand what ivor is saying about the and, and or operators and the mask. If I understand it correctly the & operator prevents you from changing a bit that is one when a mask is involved and changes all others to 0 and the | operator forces a bit to 1 when the mask is 1.
My question is when would i need to actually use the & ,| operators ?when will i need to manipulate the bits in a variable?
Find Maximum Between Three Numbers Using Ternary Operator?
Aug 23, 2014Write a program to find maximum between three numbers using ternary operator.
View Replies View RelatedSource File - Arithmetic Operator Substitution
Nov 6, 2014My goals:
1) Have some source file be read in
2) Specify what arithmetic operators to swap (+, -, /, *)
2) If an arithmetic operator is read (like a + sign etc) then we swap it with its opposite (- for example)
3) Once the swap is complete, the rest of the file stays the same even if more operators are in the file...it is then output to a file (I am going with 1mutation.java)
4) This is where it gets tricky....it then picks up where it left off to finish reading the + operators (or whatever was specified) and repeats steps 2-3 (but the operator that is already swapped gets left as it was / skipped) and the output is saved as 2mutation.java.
The most I have been able to manage is having it changed 1 operator or all of them at once. I deleted a lot of my work to start fresh / master one operator for the time being. Here is what I have:
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
public class OperatorSub {
[Code] ....
This is the data file I am using. (see attached) The file should be .java or .cpp but I stuck with .txt for now. How to tackle this? Am I on the right track?
IntelliSense - InstanceOf Operator Not Appearing Automatically
Jun 4, 2014The instanceof operator does not appear automatically(IntelliSense) when I press Ctrl+space. Instead some if condition involving instanceof is shown. What is special/unspecial about the instanceof operator not to appear in intellisense?
View Replies View RelatedGetting Int Type Cast To Lower Precision Char Type In Parasoft JTEST
Mar 11, 2014Below code I am using to typecast int to char.
char escapeValue = (char)0;
char cha = (char) 10;
escapeValue = (char)(escapeValue * cha); // Here am getting the above error.
I have 38 similar issues in my workspace.
Is Type Irrelevant As Long As Value Is Within Boundaries Of Type Of Switch Expression
Apr 30, 2014If you have final int i = 1;
short s = 1;
switch(s) {
case i: System.out.println(i);
}
it runs fine. Note that the switch expression is of type short (2 bytes) and the case constant is of type int (4 bytes).My question is: Is the type irrelevant as long as the value is within the boundaries of the type of the switch expression?I have the feeling that this is true since:
byte b = 127;
final int i = 127;
switch(b) {
case i: System.out.println(i);
}
This runs fine again, but if I change the literal assigned to i to 128, which is out of range for type byte, then the compiler complains.Is it true that in the first example the short variable and in the second example the byte variable (the switch expressions) are first implicitly converted to an int and then compared with the case constants?
How To Convert Input Array Of Type Strings To Class Type
Aug 14, 2014class Passenger{
String name;
int age;
char gender;
int weight;
public Passenger(){
[Code] ....
This is showing error.....error it gives isthat it cannot change from string type to passenger type......... How to do it??????
Addition Of Generic Type Parameter Causes Member Type Clash
Apr 22, 2014Got a problem with generics, which I'm still pretty new at. Here's a program that compiles fine:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
It's useless, but it compiles. If I change Line 14, however, to add a generic type parameter to the ListHolder class, Line 10 no longer compiles:
import java.util.ArrayList;
import javax.swing.JComponent;
public class Experiments {
public static void main(String[] args) {
ListHolder holder = new ListHolder();
[Code] ....
I get this error:
Uncompilable source code - incompatible types: java.lang.Object cannot be converted to javax.swing.JComponent
at experiments.Experiments.main(Experiments.java:10)
Apparently, the introduction of the type parameter leaves the compiler thinking that aList is of type Object. I can cast it, like this:
JComponent c = ((ArrayList<JComponent>)holder.aList).iterator().next();
That makes the compiler happy, but why is it necessary? How does adding the (unused) type parameter to the ListHolder class end up making the compiler think the aList member of an instance of ListHolder is of type Object?
Evaluation Of Expression - Operator Precedence Fixed Or Variable?
Feb 5, 2015I just wanted to ask that while evaluating any expression,is the operator precedence fixed or it varies according to the compiler ,?
View Replies View RelatedInstance Of Operator - No Output Generated Since If Condition Fails
Feb 2, 2014As per my knowledge, the instance of operator compiles only if the reference type compared to class type are in the same inheritance tree. According to that, below code should not compile but it compiles FINE!!.
Output:No output generated since the if condition fails
public class InstanceOfTest implements Inter{
public static void main(String arg[]){
Inter iot = new InstanceOfTest();
if(iot instanceof Someone) //here Inter(interface) and Someone(class) are not in the same inheritance tree.
System.out.println("iot is a Someone");
}
}
interface Inter{}
class Someone{}
How To Convert String Type To Generic Class Type
Mar 22, 2015I have a String repersentaion of some Object.I want that object convert back into some class type how can I do this?
View Replies View RelatedWhen Remove Increment Operator Program Shows Invalid Statement
Feb 19, 2015class Brain56
{
public static int[] get()
{
return null;
}
public static void main(String...a)
{
int k=1;
get()[k]++;
}
}
when i remove the increment operator(get()[k]) program shows invalid statement may i know the reason behind it?
How To Convert ZipEntry Type To File Type
Dec 4, 2014I'm trying to parse and compare the content of a zip file. However I'm stuck at what SHOULD be a very simple problem, however I can't seem to find a solution. I have done the following:
ZipInputStream zin1 = new ZipInputStream(fin);
ZipEntry ze1 = null;
fin2 = new FileInputStream(fileName2);
ZipInputStream zin2 = new ZipInputStream(fin2);
ZipEntry ze2 = null;
//fin.close();
ze1 = zin1.getNextEntry();
ze2 = zin2.getNextEntry();
Which gives me the first entry of each zipfile as a ZipEntry type object. I have tried getting the path of the file (inside the zip file) and using this to create a File type object. This does not seem to work though I get:
Exception in thread "main" java.io.FileNotFoundException: My DocumentsmetadatacoreProperties.xml (The system cannot find the file specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileReader.<init>(Unknown Source)
And this is because I get a null return from trying to create the File file1 = new File(correctLocation);
I guess I cannot access the file inside a zip file this way. So my question is how can I make a ZipEntry type object into a File type object?
Servlets :: Provide Interface To Operator To Manage Multiple Printers Of Smart Cards
May 9, 2014Part of my app is to provide an interface to an operator to manage multiple printers of smart cards.
A JSP page displays all printers and each printer has a print button.
I want the operator to press several buttons and each button pressed starts a thread.
Threads should run in parallel and pressing a button does not cancel the processing of the previous button.
Remove All Numbers From Queue And Push Onto Stack Until Operator Is Reached - Null Pointer Exception
Apr 26, 2015This method keeps throwing a NullPointerException. Not only that, but its not doing what I want it to do.
Heres the code:
/*
Remove all the numbers from the queue and push onto the stack until an operator is reached
*/
private static void processQueue() {
// Check what is at the front of the queue. If an operator is found or the queue is empty, exit method.
while(queue.front() != null || !queue.front().equals("*") || !queue.front().equals("/") || !queue.front().equals("%")
|| !queue.front().equals("+") || !queue.front().equals("-"))
{
stack.push(queue.removeFront()); // push the operand onto the stack
}
}
Here is the method that calls the processQueue() method
/*
Process the mathematical expression using a stack and a queue
*/
private static double processExpression() {
// insert all elements from the stack to the queue for processing
while(stack.top() != null) {
queue.insertBack(stack.pop());
[Code] .....