Cannot Use Variables Inside A Case In Switch Construct?
Mar 1, 2015
If I have an integer variable like int a=9 then in the switch case If i write
switch(a) {
case 4+a: System.out.println("hii");
}
Then why is this statement a compile-time error that variables cannot be used inside a case statement why does the compiler not subtitutes the values in place of the variables.
So basically what problem it creates for which the language developers did not include it as a proper syntax,is there any reason behimd this because of jump table?
I am stuck with two switch statements that I feel I am close to achieving. My first switch statement is to generate random mathematical operators for the math questions in the game (generated randomly) My second switch statement is to determines which action the system will take upon the correct or incorrect answer. For the first switch statement I have a variable called num. Num is a random integer. I have an operator mapped to each outcome of num. In my second switch statement I am trying to use the variable answer as a variable in the first case but do not know how.
package pkgnew; import java.util.Scanner; import java.util.Random; public class New { public static void main(String args[]) { //Declare and construct variables
New to java/programming and i cant understand why the pen variable does not display the the correct value ... For example for input 1 ; 2 ; 3 ; 4 both variables will display 10 and i dont understand why pen does not have the value 6 .
import acm.program.*; public class Chap4_ex12 extends ConsoleProgram { public void run () { int pen = 0; int r = 1; int sum = 0; while (r !=SANTINEL) { r = readInt(" ? "); pen=sum ;
why this switch code does not work for the 'Q'. Everything works fine for the other cases, i.e. 1,2,3, and 'q', but when I type in 'Q', I get the default case. Please note all the values have been defined in an earlier part of the code but for simplicity's sake I have removed them below
do { switch (choix) { //demande le nombre de patons a achete case '1':
I am making a programme for a calculator to - Divide, multiply, add and subtract. I have the code written but when I am running it and trying to add it was for some subtracting ....
import javax.swing.JOptionPane; public class calculator3 { public static void main(String[] args){ String number1,number2,operatorstring; double result=0,a,b;
int grade = 68; switch (grade) { case 100: System. out.println( "You got an A. Great job!" ); break; case 80: System. out.println( "You got a B. Good work!"); break;
Basically the problem is I've been trying to loop my switch (if this is even possible) until the user enters a correct number between 1 and 4. But for some reason when the user enters a correct number (1,2,3,4) the loop runs again. Even when the user enters a wrong number the switch ignores the default and repeats what is in the do.
Am I just trying to loop something that cannot be looped or have I gone?
I have create as short example which contains two classes Cat and Dog followed by a switch statement in the main method.
Class Cat
public class Cat { private String name; //Setter public void setName(String pName) {name = pName;} //Getter public String getName() {return name;} // Constructor public Cat(String catName) {name = catName;}
[code]....
My Issue is that after creating the objects within the switch statement, is there a way to return the objects back to the main method once created within the switch ?
cannot break from while loop. Whenever I am trying to exit from startCustomerManagement-> backEnd() -> mainScreen()..It gets stuck between mainScreen and backEnd screen. However I can exit from backEnd()->startCustomerManagement() screen
/* * To change this license header, choose License Headers in Project Properties. * To change this template file, choose Tools | Templates * and open the template in the editor. */ package javaapplication19; import java.io.BufferedReader;
import java.util.Scanner; class test{ public static void main ( String[] args ) { Scanner scan = new Scanner ( System.in ); int choice = scan.nextInt();
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 have an issue with variables/attributes scope inside a jsp tag file.
In short, I have a tag with an attribute named "id". If the page using my tag has a variable called "id" (maybe coming from the spring model) and I call my tag WITHOUT specifying the id attribute, inside my tag I still can acces to the "id" attribute that was defined in the page but I don't want this behavior; if the tag is called without the "id" attribute then it should defaults to empty/null.
(...) The id is: ${id} // <- Prints 'X' <my:print /> <- Prints 'X' ! I want it to not print anything in that case <my:print id="Y"/> <- Prints 'Y' (...)
What I want is to have the tag attributes live only in the tag, without having any knowledge of any variable outside of the tag itself. Is it possible?
My current workaround is to remove the "id" attribute, enable dynamic attributes and with a scriptlet search in the dynamic attributes map for the "id" and save it in a variable with a different name (e.g. "__id").
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)
//construct and populate the Time menu Menu mnuTime = new Menu("Time", true); mnuBar.add(mnuTime); MenuItem mnuCurrentTime = new MenuItem("CurrentTime"); mnuTime.add(mnuCurrentTime);
[Code] ....
E:Calculator.java:64: error: cannot find symbol if (arg == "Time") ^ symbol: variable arg location: class Calculator 1 error
In other words in a table view with several editable columns, when a new row is added this row does not contain any column cells yet. Cells are added on demand once a column gains focus and starts editing. Is this the case? Is there any way to force the row to construct all cells eagerly?
I am working on writing a desktop based email client using swing. First some specifics: I need to show emails in a (dynamically updatable) vertical list. Each item in this vertical list would represent an email showing: (a) the subject, (b) a photo of the sender that I have locally available & a couple of buttons. So, I plan to create a JPanel containing a JLabel to show the Subject, The photo inside a JLabel & JButtons. I have the layout of this panel done and is not a problem.
My problem is with stacking all these JPanels (each representing an email) and showing them on the UI as a list. I am not sure of any way to do this. Moreover, when a new email is received, it has to be displayed at the top of the list (not at the bottom).
Specifically, I need a good way of displaying a vertical list of JPanels & be able to add new JPanels at the top of the list.
I am trying to write a program that read from a csv file called matches.csv ... A single football match can end with a win or a draw: in first case the winner team get 3 points and the loser none, in the second case of draw each of the two teams get 1 point.
In the file it contains the following data.
17/08/2013 Arsenal Aston Villa 1 3 24/08/2013 Aston Villa Liverpool 0 1
This means that a match has been played on the 17/08/2013 where Arsenal scored 1 goal while Aston Villa 3 goals: thus Arsenal got 0 points while Aston Villa 3 points.
How can I structure my output to make it make it read
Position Team Played Points 1 Aston Villa 2 3 2 Liverpool 1 3 3 Arsenal 1 0
My code so far:
import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; public class Teams { public static void main(String[] args) { String fileName = "matches.csv";
So I am having trouble with trying to get the main method to work. The program is supposed to construct a BinaryTree, and deserialize a file that is used for the Tree.
I'm trying to create a simple java math question quiz using random operators, but keep sinking myself into deeper despair. The numbers must range from 0-9 and given an operator: +,-,/,*,%. Can't create a new method or use Case statements. The code isn't finished but don't want to make it any worse.
package marco; import java.util.Scanner; import java.util.Random; public class Project { public static void main(String[] args) { Scanner keyboard = new Scanner(System.in); Random rand = new Random(); System.out.println("How many questions do you want?");
I am getting the following exception because of the **ui include** tag in template.xhtml. Is the src attribute of ui include is wrong.:
javax.faces.FacesException: Could not resolve NavigationCase for outcome: index at org.primefaces.renderkit.OutcomeTargetRenderer.getTargetURL(OutcomeTargetRenderer.java:86) at org.primefaces.component.menu.BaseMenuRenderer.encodeMenuItem(BaseMenuRenderer.java:162) at org.primefaces.component.tabmenu.TabMenuRenderer.encodeItem(TabMenuRenderer.java:89)
If my file name is MyBigXMLFile.xml it won't delete but if I rename it to mybigxmlfile.xml it will delete. How do you get around the case sensitive issue?
