While practicing java i have came across boolean data type. i have executed below program but i am not sure how i got output of the program like below:
10 > 9 is true
Here is my program:
class BoolTest3
{
public static void main(String args[])
{
System.out.println("10 > 9 is "+(10>9));
}
}
My question is: how this program will come to know that 10>9 true or false.. how bolean data type used in this program.
Here is a code and error .....
View Replies View RelatedIm trying to do this
if( 2/2 ) {
system.out.println( "number is not event" );
} else {
system.out.println( "number is event" );
}
However if statement requires a return of type boolean. So im forced to this instead
if( (2/2) != 0 ) {
system.out.println( "number is not event" );
} else {
system.out.println( "number is event" );
}
Is there a way to achieve the former method, without typecasting, if you had to typecast how do you do it?
I searched everywhere but i didn't found anything about the real size of primitive boolean type used by java.
View Replies View Relatedmethod passing null to the called function, compiler would take that parmer as what type of paramer???
View Replies View RelatedI am trying to write a password checker program and thats the error i get. (the final error!) but this one i dont know how to fix. here is my code.
/* Text
Text
text
*/
import java.util.Scanner; // Imports the Scanner class to get Keyboard Inputs
class PriceRichardChapter5Test
{
public static void main (String [] args) {
String Password; // Creates the Password variable
[Code] .....
I am getting notification about "The value of the local variable result not used" in my program when i am using boolean data type.But code execution was successful. Results are also displayed accurately.I am using Eclipse, there i i have noticed this warning.
* program to practice about comparison operators */
public class compoperators {
public static void main(String[] args) {
boolean result;
}
[code]....
I was wondering is there any data type that can store method?
View Replies View Relatedi need to create an array with attributes name, gender, phone, age.and then sort acording to age in ascending order.
i created like this,
public class Array{
private String[] name={"ram", "katy", "priti", "john"};
private String[] gender={"male","female","female","male"};
private int[] phone={989898089,89898989,8982989089,898908989};
private int[] age={45,24,30,28};
public void printarray(){
[code]....
This code sorts the age attribute alone and when printing ouput it swaps one person's age to other person, how to make it correct
I am totally new to Java. What is the purpose of this method?
Flow of the int x=3; like where does the 3 go step by step?
Passing Primitive Data Type Arguments (from oracle java tutorials)
Primitive arguments, such as an int or a double, are passed into methods by value. This means that any changes to the values of the parameters exist only within the scope of the method. When the method returns, the parameters are gone and any changes to them are lost. Here is an example:
public class PassPrimitiveByValue {
public static void main(String[] args) {
int x = 3;
// invoke passMethod() with
// x as argument
passMethod(x);
[Code] ....
I was struggling to use BufferedReader to extract some data and then perform some calculations and then have the results as outputs.
I haven't quite solved that issue but in order to progress, I hard coded some values into my application and proceeded with the actual calculation loops etc.
Currently, the value out put from one of my calculations is given as:
1.1704926E7
How can I make the console show it in a natural way. I've performed the calculation manually and it should be 11704926.5 I don't want to lose that .5!
Primitive arguments, such as an int or a double, are passed into methods by value. This means that any changes to the values of the parameters exist only within the scope of the method. When the method returns, the parameters are gone and any changes to them are lost.
Reference data type parameters, such as objects, are also passed into methods by value. This means that when the method returns, the passed-in reference still references the same object as before. However, the values of the object's fields can be changed in the method, if they have the proper access level.For example, consider a method in an arbitrary class that moves Circle objects:
public void moveCircle(Circle circle, int deltaX, int deltaY) {
// code to move origin of
// circle to x+deltaX, y+deltaY
circle.setX(circle.getX() + deltaX);
circle.setY(circle.getY() + deltaY);
// code to assign a new
// reference to circle
circle = new Circle(0, 0);
}
Let the method be invoked with these arguments: moveCircle(myCircle, 23, 56)
Inside the method, circle initially refers to myCircle. The method changes the x and y coordinates of the object that circle references (i.e., myCircle) by 23 and 56, respectively. These changes will persist when the method returns. Then circle is assigned a reference to a new Circle object with x = y = 0. This reassignment has no permanence, however, because the reference was passed in by value and cannot change. Within the method, the object pointed to by circle has changed, but, when the method returns, myCircle still references the same Circle object as before the method was called.
I am trying to use double data type in a for loop for precise operations and just to see if there could be any problem doing that I tested a small code :
public class doubleLimit {
public static void main(String[] args){
for(double i=-0.1;i<=0;i+=0.01)
System.out.println(i); }}
The output I was expecting is :
-0.1
-0.09
-0.08
-0.07
-0.06
-0.05
-0.04
-0.03
-0.02
-0.01
0.00
But the output of the code is :
-0.1
-0.09000000000000001
-0.08000000000000002
-0.07000000000000002
-0.06000000000000002
-0.05000000000000002
-0.040000000000000015
-0.030000000000000013
-0.02000000000000001
-0.01000000000000001
-1.0408340855860843E-17
Why is the code not working the way I expected, I think it has something to do with any property of double but I am not sure.
Is this the proper way to add to a generic list? My code works just fine, but I got this feeling that there might be some kind of flaw in it or something. Is this pretty much the basic way to add any type of data to a generic list?
import java.util.LinkedList;
public class ListOfGeneric<E> {
private LinkedList<E> myList;
ListOfGeneric(){
myList = new LinkedList<E>();
[Code] ....
public class InputFileData {
/**
* @param inputFile a file giving the data for an electronic
* equipment supplier’s product range
* @return an array of product details
* @throws IOException
*/
public static Product [] readProductDataFile(File inputFile)
throws IOException{
// YOUR CODE HERE
}
This code is meant to be used to read a text file and store the data in an array of type Product[]. I know how to read in a text file and have it sort it into an array, but I've never seen code laid out in this fashion before (specifically "public static Product[]", and I'm unsure how to work with "(File inputfile)". I've looked all over the place but can't find any examples of anything like this.
Also, the code given cannot be changed, as it's that code I have to work with.
I still don't understand how to use it as a whole. For example, do I read the file in the main and have this method read that in and output to the Product class? Do I read the file in this method? I can't work out how to make this work when I have to use this method.
In my project i am facing an problem, The My SQL Data base will accept the date format of yyyy/mm/dd only as "Date" data type but in my program i wants to use dd/mm/yyyy format. (i have this same format now) that's why I am unable to insert / retrieve it..
View Replies View RelatedI have doubt in generics,
List<int> c=new ArrayList<int>();
why we cannot use primitive data type like int,double.
Oracle JDBC driver determine the DATE data type of parameter correctly without any typecasting.
Example:
ps = conn.prepareStatement("SELECT ? FROM DUAL");
ps.setObject(1, Date.valueOf("2014-01-11")) ;
I have tried the same example with other database driver but it gives error.
PostgreSQL JDBC driver:
org.postgresql.util.PSQLException: ERROR: could not determine data type of parameter $1
ps = conn.prepareStatement("SELECT ?");
ps.setObject(4, Date.valueOf("2005-01-01"));
so I want to know how Oracle JDBC driver determine the DATE data type of parameter.
Oracle JDBC driver determine the DATE data type of parameter correctly without any typecasting.
Example:
ps = conn.prepareStatement("SELECT ? FROM DUAL");
ps.setObject(1, Date.valueOf("2014-01-11"));
How Oracle JDBC driver determine the DATE data type of parameter.
I have created an enumerated data type that represents months. In my program I have asked the user for the month. I hold the month entered by user into a string variable. From that string variable I'm trying to display the month using my enumerated data type. I know I can use if statements, but is there another simple way to do it?
import java.util.Scanner;
public class demo {
//Enum class called month that has constants in it representing months
enum month{january,february,march,april,may,june, july,august,september,
october,november, december};
[Code] ....
I am trying to implement product method below which returns the set representing the Cartesian product of the current set and a given set (the Cartesian product contains all ordered pairs (a, b) where a belongs to the current set, and b belongs to the given set). The product should be a ListSet <Tuple<E>> object where each ordered pair is a Tuple element. (I have a Tuple class which implements an ordered tuple)
What am I trying to do in the product method : Make 2 for loop and inside the for loop make an array of <E> then set the 2 elements of the tuple then again set tuple and add it to arrayList. how to set 2 elements of the tuple and set tuple ??
public class ListSet<E> implements Iterable<E>{
SinglyLinkedList<E> sl;
public ListSet(){
sl = new SinglyLinkedList<E>();
[code]....
What I'm doing about it: googling the shit out of my problems, consulting you fine readers, consulting my friends, and yesterday I signed up for Lynda.com. I'm hoping 30hrs+ or so of watching, rewatching, and analyzing the example code will catch me up before I get too behind in CS302
** Assignment Prompt **
Integer types are very convenient, but their limited width and precision makes them unsuitable for some applications where precision is more important than speed. Develop a class VeryLargeInteger that can handle arbitrary long integer numbers (both negative and positive) and the basic arith- metic operations (addition, subtraction, multiplication, division, and remainder).
Hint: The number could be represented as string, the sign could be represented either as boolean or as part of the string.
Note: Implementations of addition/subtraction through repeated use of a constant incremen- t/decrement will not be accepted. Implementations of multiplication and division that rely only on addition and subtraction will not be accepted.
I know I'm going to have to create a separate tester to call on the VeryLargeInteger class and it's math methods. For the new data type, should I convert the integer/string into an array in order to handle the large length of the number? I know he wants us to use recursion for the math methods. My gut tells me addition and subtraction will be slightly easier than multiplication and division. I know I'll have to reference the other methods for division. We aren't allowed to use the BigInteger class.
How I should construct any of the methods.
Java Code:
import java.util.ArrayList;
/**
∗ VeryLargeInteger (VLI) is a class for arbitrary precision integer computation
*/
public class VeryLargeInteger {
private int[] num1;
private int[] num2;
private int[] num3;
[code]....
How to get a double data type in order to display in the view through a servlet:
objReferencias.setImprevistos(request.("imprevistos"));
Question:
request.getDouble("imprevistos));? or
request.getDoubleParameter("imprevistos));?
I've been searching but I have not found the appropriate answer.
Okay, I am supposed to implement the functionalities of the Set class using a private data member of type ListReferencedBased<E>,how the ListReferenceBased works with what I am trying to accomplish.I am trying to complete Set.java, and I have barely started and much of the code doesn't work. ListReferenceBased was given to me completed.
import java.util.Iterator;
pubic class ListReferenceBased<E> implements ListInterface<E>, Iterable<E>{
/** reference to the first element of the list */
private Node<E> head;
/** number of items in list */
private int numItems;
[code]....
I have a code in which I am reading input from System.in and Destination is some where else
Here is my code
File file=new File("D:/output.txt");
OutputStream os=new java.io.FileOutputStream(file);
Scanner scanner=new Scanner(System.in);
System.out.println("Enter Data to write on File");
String text=scanner.nextLine();
int c=Integer.parseInt(text);
int a;
while((a=c.read())!=-1)
os.write(a);
System.out.println("File Written is Successful");
In the line while((a=c.read())!=-1)
a compile time error is shown "cannot invoke read on primitive data type int"
Where I am going wrong?
How can insert value into sql server column of data type 'datetime' with jdbc the methods in java.sql are 'setdate()' and 'setTime()'
How can I do this. I'm using java.time.LocalDateTime.