/**************************/
/* INFORMATION SECTION */
/* MRS. CHAVES */
/* 5 NOVEMBER 2020 */
/* METHOD EXAMPLE */
/**************************/
/*************************************/
/* PROGRAM DESCRIPTION SECTION */
/* THIS PROGRAM IS A TRY LAB TO SHOW */
/* THE USE OF JAVA METHODS */
/*************************************/
package program_sample;
/******************/
/* IMPORT SECTION */
/******************/
import javax.swing.JOptionPane; // USED FOR WINDOWS
public class methodTryLab
{
public static void main(String[] args)
{
/*************************/
/* ERROR MESSAGE SECTION */
/*************************/
final String ERROR2 = "MONEY must be a POSITIVE value!!";
final String ERROR3 = "PEOPLE must be a POSITIVE value!!";
final String ERROR4 = "ANSWER must be y, Y, d, or N!!";
/******************/
/* PROMPT SECTION */
/******************/
final String PROMPT1 = "Input your NAME: ";
final String PROMPT2 = "Input how much MONEY: $";
final String PROMPT3 = "Input number of PEOPLE: ";
final String PROMPT4 = "Input run program again (Y, y, N, n): ";
/********************/
/* VARIABLE SECTION */
/********************/
String name; // USER'S NAME
double money; // TOTAL AMOUNT OF MONEY
int numPeople; // NUMBER OF PEOPLE
char runProgram; // RUN PROGRAM Y OR N
double share; // SHARE PER PERSON
/********************************/
/* FUNCTION PROGRAM DESCRIPTION */
/********************************/
programDescription ();
/*****************/
/* INPUT SECTION */
/*****************/
/**************************************/
/* LOOP TO RUN PROGRAM MORE THAN ONCE */
/**************************************/
do
{
/************************/
/* METHOD TO INPUT NAME */
/************************/
name = inputString (PROMPT1);
/*************************/
/* METHOD TO INPUT MONEY */
/*************************/
money = inputDouble (PROMPT2, ERROR2);
/*************************************/
/* METHOD TO INPUT NUMBER OF PEOPLE */
/*************************************/
numPeople = inputInt (PROMPT3, ERROR3);
/******************************************/
/* METHOD TO CALCULATE SHARE PER PERSON */
/******************************************/
share = calculateShare (money, numPeople);
/***********************************/
/* METHOD TO PRINT OUT INFORMATION */
/***********************************/
printInfo (name, money, numPeople, share);
/**************************************************/
/* METHOD TO INPUT AANSWER TO RUN PROGRAM AGAIN */
/**************************************************/
runProgram = inputChar ('y', 'n', PROMPT4, ERROR4);
}
while ((runProgram == 'y') || (runProgram == 'Y'));
}
/*************************************************************/
/* METHOD SECTION */
/*************************************************************/
public static double calculateShare (double mny, int nmPpl)
/*********************************************************/
/* PRECONDITION: USER INPUTS MONEY AND NUMBER OF PEOPLE */
/* POSTCONDITION: METHOD CALCULATES SHARE PER PERSON */
/*********************************************************/
{
double personShare = 0; // LOCAL VARIABLE SHARE PER PERSON
personShare = mny / (double) nmPpl; // CALCULATE SHARE PER PERSON
return (personShare); // RETURN SHARE PER PERSON
}
public static String inputString (String prmpt)
/****************************************/
/* PRECONDITION: USER NEEDS A STRING */
/* POSTCONDITION: USER INPUTS AN STRING */
/****************************************/
{
String str; // USER INPUTS A STRING
str = JOptionPane.showInputDialog (null, prmpt, "INPUT STRING",
JOptionPane.QUESTION_MESSAGE);
return (str); // RETURN INPUTTED STRING
}
public static char inputChar (char c1, char c2, String prmpt, String err)
/*******************************************************/
/* PRECONDITION: USER NEEDS A CHARACTER */
/* POSTCONDITION: READS IN A CHARACTER AND LOOPS UNTIL */
/* THE CORRECT CHARACTER IS INPUTTED */
/*******************************************************/
{
char ans; // INPUTTED CHARACTER
/*************************************/
/* LOOP UNTIL VALID CHAR IS INPUTTED */
/*************************************/
do
{
ans = JOptionPane.showInputDialog (null, prmpt, err,
JOptionPane.QUESTION_MESSAGE).charAt(0);
/*******************************************/
/* FUNCTION TO ERROR CHECK VALID CHARACTER */
/*******************************************/
if ((ans != c1) && (ans != Character.toUpperCase(c1)) &&
(ans != c2) && (ans != Character.toUpperCase(c2)))
{
printErrorMessage (err);
}
}
while ((ans != c1) && (ans != Character.toUpperCase(c1)) &&
(ans != c2) && (ans != Character.toUpperCase(c2)));
return (ans);
}
public static double inputDouble (String prmpt, String err)
/**********************************************************/
/* PRECONDITION: PROGRAM NEEDS A DOUBL VALUE */
/* POSTCONDITION: PROMPT USER FOR A DOUBLE VALUE TO INPUT */
/* LOOPS UNTIL CORRECT VALUE IS INPUTTED */
/*********************************************************/
{
double num; // inputted double value
/***************************************/
/* LOOP UNTIL VALID DOUBLE IS INPUTTED */
/***************************************/
do
{
num = Double.parseDouble(JOptionPane.showInputDialog(null,
prmpt, err, JOptionPane.QUESTION_MESSAGE));
/****************************/
/* ERROR CHECK VALID DOUBLE */
/****************************/
if (num <= 0)
{
printErrorMessage (err); // METHOD CALL PRINT ERROR MESSAGE
}
}
while (num <= 0);
return (num); // RETURN DOUBLE VALUE
}
public static int inputInt (String prmpt, String err)
/************************************************************/
/* PRECONDITION: PROGRAM NEEDS AN INTEGER VALUE */
/* POSTCONDITION: PROMPT USER FOR AN INTEGER VALUE TO INPUT */
/* LOOPS UNTIL CORRECT VALUE IS INPUTTED */
/************************************************************/
{
int num; // inputted int value
/****************************************/
/* LOOP UNTIL VALID INTEGER IS INPUTTED */
/****************************************/
do
{
num = Integer.parseInt(JOptionPane.showInputDialog(null,
prmpt, err, JOptionPane.QUESTION_MESSAGE));
/*************************/
/* ERROR CHECK VALID INT */
/*************************/
if (num <= 0)
{
printErrorMessage (err); // METHOD CALL PRINT ERROR MESSAGE
}
}
while (num <= 0);
return (num);
}
public static void printErrorMessage (String err)
/*****************************************************/
/* PRECONDITION: USER NEEDS A CORRECT VALUE */
/* POSTCONDITION: PRINT OUT ERROR MESSAGE IF INVALID */
/*****************************************************/
{
JOptionPane.showMessageDialog(null, err, "ERROR – INCORRECT VALUE",
JOptionPane.ERROR_MESSAGE);
}
public static void printInfo (String nm, double mny, int nmPpl, double shr)
/*************************************************/
/* PRECONDITION: PROGRAM HAS CALCULATE SHARE */
/* POSTCONDITION: PROGRAM PRINTS OUT INFORMATION */
/*************************************************/
{
JOptionPane.showMessageDialog(null, String.format("OUTPUT INFORMATION\n\n" +
"NAME: " + nm +
"\nMONEY: $%.2f" + mny +
"\nNUMPEOPLE: " + nmPpl +
"\nSHARE: $%.2f" + shr +
"\n\nPress OK to continue . . ."),
"SHARE PER PERSON",
JOptionPane.PLAIN_MESSAGE);
}
public static void programDescription ()
/*******************************************************/
/* PRECONDITION: USER NEEDS PROGRAM DESCRIPTION */
/* POSTCONDITION: PRINTS PROGRAM DESCRIPTION TO SCREEN */
/*******************************************************/
{
/****************************/
/* USER DESCRIPTION SECTION */
/****************************/
JOptionPane.showMessageDialog(null, "TRY LAB\n\nThis program will " +
"ask you to input an \n amount of money " +
"and number of people to share it with " +
"and it will calculate the share per person." +
"\n\nPress OK to continue . . .",
"SHARE CALCULATOR", JOptionPane.INFORMATION_MESSAGE);
}
}
Write, Run & Share Java code online using OneCompiler's Java online compiler for free. It's one of the robust, feature-rich online compilers for Java language, running the Java LTS version 17. Getting started with the OneCompiler's Java editor is easy and fast. The editor shows sample boilerplate code when you choose language as Java and start coding.
OneCompiler's Java online editor supports stdin and users can give inputs to the programs using the STDIN textbox under the I/O tab. Using Scanner class in Java program, you can read the inputs. Following is a sample program that shows reading STDIN ( A string in this case ).
import java.util.Scanner;
class Input {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Enter your name: ");
String inp = input.next();
System.out.println("Hello, " + inp);
}
}
OneCompiler supports Gradle for dependency management. Users can add dependencies in the build.gradle file and use them in their programs. When you add the dependencies for the first time, the first run might be a little slow as we download the dependencies, but the subsequent runs will be faster. Following sample Gradle configuration shows how to add dependencies
apply plugin:'application'
mainClassName = 'HelloWorld'
run { standardInput = System.in }
sourceSets { main { java { srcDir './' } } }
repositories {
jcenter()
}
dependencies {
// add dependencies here as below
implementation group: 'org.apache.commons', name: 'commons-lang3', version: '3.9'
}
Java is a very popular general-purpose programming language, it is class-based and object-oriented. Java was developed by James Gosling at Sun Microsystems ( later acquired by Oracle) the initial release of Java was in 1995. Java 17 is the latest long-term supported version (LTS). As of today, Java is the world's number one server programming language with a 12 million developer community, 5 million students studying worldwide and it's #1 choice for the cloud development.
short x = 999; // -32768 to 32767
int x = 99999; // -2147483648 to 2147483647
long x = 99999999999L; // -9223372036854775808 to 9223372036854775807
float x = 1.2;
double x = 99.99d;
byte x = 99; // -128 to 127
char x = 'A';
boolean x = true;
When ever you want to perform a set of operations based on a condition If-Else is used.
if(conditional-expression) {
// code
} else {
// code
}
Example:
int i = 10;
if(i % 2 == 0) {
System.out.println("i is even number");
} else {
System.out.println("i is odd number");
}
Switch is an alternative to If-Else-If ladder and to select one among many blocks of code.
switch(<conditional-expression>) {
case value1:
// code
break; // optional
case value2:
// code
break; // optional
...
default:
//code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition. Usually for loop is preferred when number of iterations is known in advance.
for(Initialization; Condition; Increment/decrement){
//code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while(<condition>){
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (<condition>);
Class is the blueprint of an object, which is also referred as user-defined data type with variables and functions. Object is a basic unit in OOP, and is an instance of the class.
class keyword is required to create a class.
class Mobile {
public: // access specifier which specifies that accessibility of class members
string name; // string variable (attribute)
int price; // int variable (attribute)
};
Mobile m1 = new Mobile();
public class Greeting {
static void hello() {
System.out.println("Hello.. Happy learning!");
}
public static void main(String[] args) {
hello();
}
}
Collection is a group of objects which can be represented as a single unit. Collections are introduced to bring a unified common interface to all the objects.
Collection Framework was introduced since JDK 1.2 which is used to represent and manage Collections and it contains:
This framework also defines map interfaces and several classes in addition to Collections.
| Collection | Description |
|---|---|
| Set | Set is a collection of elements which can not contain duplicate values. Set is implemented in HashSets, LinkedHashSets, TreeSet etc |
| List | List is a ordered collection of elements which can have duplicates. Lists are classified into ArrayList, LinkedList, Vectors |
| Queue | FIFO approach, while instantiating Queue interface you can either choose LinkedList or PriorityQueue. |
| Deque | Deque(Double Ended Queue) is used to add or remove elements from both the ends of the Queue(both head and tail) |
| Map | Map contains key-values pairs which don't have any duplicates. Map is implemented in HashMap, TreeMap etc. |