Sunday, 26 March 2023
Saturday, 16 July 2022
Thursday, 12 August 2021
Java introduction- Online notes while explaining
Thursday, 1 July 2021
Java Program to add new element, its atomic number and atomic weight, sort based on atomic number and search based on element name
A
chemist needs to record data of elements in periodic table. Draw the class
diagram and develop the classChemicalElement with name, atomicNum
andatomicWeight as private attributes. Code the constructorand toString()
method. The main() method inChemicalDemo class must store data of chemicals in
acollection and is menu driven with the followingoptions: a) Add new element,
b)sort based onatomicNum and c)search based on name.
Sol:
Class
Diagram:
|
package key;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;
class ChemicalElement
{
private String name;
private int atomicNum;
private float atomicWeight;
public ChemicalElement(String name, int atomicNum, float atomicWeight)
{
this.name = name;
this.atomicNum = atomicNum;
this.atomicWeight = atomicWeight;
}
public String getName() {
return name;
}
public int getAtomicNum() {
return atomicNum;
}
public String toString() {
return "name=" + name + ", atomicNum=" + atomicNum + ", atomicWeight=" + atomicWeight;
}
}
class SortByAtomicNumber implements Comparator<ChemicalElement>
{
public int compare(ChemicalElement c1, ChemicalElement c2)
{
return (int)(c1.getAtomicNum()-c2.getAtomicNum());
}
}
public class ChemicalDemo
{
static ArrayList<ChemicalElement> cel= new ArrayList<ChemicalElement>();
static Scanner sc = new Scanner(System.in);
public static void main(String[] args)
{
while(true)
{
System.out.println("enter 1.
Add new element 2. sort based on atomicNum 3. search based on name 4.
exit");
int choice=sc.nextInt();
switch(choice)
{
case 1:
System.out.println("enter name, atomic number and its
atomic weight");
cel.add(new ChemicalElement(sc.next(),sc.nextInt(),sc.nextFloat()));
break;
case 2:
System.out.println("sorted
names based on atomic number");
Collections.sort(cel,new
SortByAtomicNumber());
for(ChemicalElement ob:cel)
System.out.println(ob);
break;
case 3:
System.out.println("enter name
to be searched");
String
key=sc.next();
for(ChemicalElement ob:cel)
if(ob.getName().equals(key))
{
System.out.println(ob);
break;
}
break;
case 4:
return;
default:
System.out.println("invalid
choice");
}
}
}
}
enter 1. Add new element 2. sort based on atomicNum 3. search based on name 4. exit
1
enter name, atomic number and its atomic weight
hydrogen
1
1.007
enter 1. Add new element 2. sort based on atomicNum 3. search based on name 4. exit
1
enter name, atomic number and its atomic weight
helium
2
4.002
enter 1. Add new element 2. sort based on atomicNum 3. search based on name 4. exit
2
sorted names based on atomic number
name=hydrogen, atomicNum=1, atomicWeight=1.007
name=helium, atomicNum=2, atomicWeight=4.002
enter 1. Add new element 2. sort based on atomicNum 3. search based on name 4. exit
3
enter name to be searched
helium
name=helium, atomicNum=2, atomicWeight=4.002
enter 1. Add new element 2. sort based on atomicNum 3. search based on name 4. exit
4
Java Program to add Football player details and sort them by number of players
A university records data of its
Football players. Drawthe class diagram and develop the class
FootballPlayerwith name, numberOfGoals and numberOfMatches.Code the
constructor, toString() method. The main()method in Demo class must store data
of footballplayers in a collection and is menu driven with thefollowing
options: a) Add new player b)sort by numberof goals.
Class diagram
|
FootballPlayer.java
package key;
public class FootballPlayer
{
private String name;
private int numberOfGoals,numberOfMatches;
public int getNumberOfGoals() {
return numberOfGoals;
}
public void setNumberOfGoals(int numberOfGoals) {
this.numberOfGoals = numberOfGoals;
}
public FootballPlayer(String name, int numberOfGoals, int numberOfMatches)
{
this.name = name;
this.numberOfGoals = numberOfGoals;
this.numberOfMatches = numberOfMatches;
}
public String toString()
{
return "name=" + name + ", numberOfGoals=" + numberOfGoals + ", numberOfMatches="
+
numberOfMatches;
}
}
Demo.java
package key;
import java.util.*;
class SortByNumberOfGoals implements Comparator<FootballPlayer>
{
public int compare(FootballPlayer f1,FootballPlayer f2 )
{
return (int)(f1.getNumberOfGoals() -f2.getNumberOfGoals());
}
}
public class Demo
{
public static void main(String[] args)
{
List<FootballPlayer>
fp = new
ArrayList<FootballPlayer>();
Scanner sc= new Scanner(System.in);
while(true)
{
System.out.println("enter 1.
Add new player 2.sort by numberof goals 3. exit");
int choice=sc.nextInt();
switch(choice)
{
case 1:
System.out.println("enter
player name, number of goals, numbe of matches");
fp.add(new FootballPlayer(sc.next(),sc.nextInt(),sc.nextInt()));
break;
case 2:
System.out.println("sorted
players list based on number of goals");
Collections.sort(fp,new SortByNumberOfGoals());
for(FootballPlayer ob:fp)
System.out.println(ob);
break;
case 3:
return;
default:
System.out.println("invalid
choice");
}
}
}
}
Output:
enter 1. Add new
player 2.sort by numberof goals 3. exit
1
enter player name,
number of goals, numbe of matches
sarvani
34
20
enter 1. Add new
player 2.sort by numberof goals 3. exit
1
enter player name,
number of goals, numbe of matches
lakshmi
12
40
enter 1. Add new
player 2.sort by numberof goals 3. exit
2
sorted players list
based on number of goals
name=lakshmi,
numberOfGoals=12, numberOfMatches=40
name=sarvani,
numberOfGoals=34, numberOfMatches=20
enter 1. Add new
player 2.sort by numberof goals 3. exit
3