List of Java Programs

1. Program1 – WAP to display the List of even numbers
2. Program2 – Factorial of a number
3. Program3 – Compare Two Numbers using else-if
4. Program4 – Determine If Year Is Leap Year
5. Program5 – Fibonacci Series
6. Program6 – Palindrome Number
7. Program7- Generate prime numbers between 1 & given number
8. Program8- Pyramid of stars using nested for loops
9. Program9 – Reversed pyramid using for loops & decrement operator.
10. Program10 – Nested Switch
11. Program11 – Calculate Circle Area using radius
12. Program12 – Factorial of a number using recursion
13. Program13 – Pyramid of numbers using for loops
14. Program14 – To Find Maximum of Two Numbers.
15. Program15 – To Find Minimum of Two Numbers using conditional operator
16. Program 16 – Write a program that will read a float type value from the keyboard and print the following output.
->Small Integer not less than the number.
->Given Number.
->Largest Integer not greater than the number.
17. Program 17 – Write a program to generate 5 Random nos. between 1 to 100, and it should not follow with decimal point.
18. Program 18 – Write a program to display a greet message according to Marks obtained by student
19. Program 19 – Write a program to find SUM AND PRODUCT of a given Digit.
20. Program 20 – Write a program to find sum of all integers greater than 100 and less than 200 that are divisible by 71
21. Program 21 – Write a program to concatenate string using for Loop
22. Program 22 – Program to Display Multiplication Table
23. Program 23 – Write a program to Swap the values
24. Program 24 – Write a program to convert given no. of days into months and days.(Assume that each month is of 30 days)
25. Program 25 – Write a program to Display Invert Triangle using while loop.
26. Program 26 – Write a program to find whether given no. is Armstrong or not.
27. Program 27 – switch case demo
28. Program 28 – Write a program to generate Harmonic Series.
29. Program 29 – Write a program to find average of consecutive N Odd numbers and even numbers.
30. Program 30 – Display Triangle as follow: (using for loops)
1
2 3
4 5 6
7 8 9 10 … N */
 
Programs to work out
1.WAP to display a color name depending on color value
using switch.
2. Accepting single character, int, float, string and
double value from the keyboard.
3. To grade the students using switch and if-else.
4. To compute the power of 2 using for loop
5. To find the sum of the digits of a given integer number 2
6. Given the month , identify the season using switch.
 

Program1 – List of even numbers

/*
List Even Numbers Java Example
This List Even Numbers Java Example shows how to find and list even
numbers between 1 and any given number.
*/
public class ListEvenNumbers {
public static void main(String[] args) {
//define limit
int limit = 50;
System.out.println(“Printing Even numbers between 1 and ” +
limit);
for(int i=1; i <= limit; i++){
// if the number is divisible by 2 then it is even
if( i % 2 == 0){
System.out.print(i + ” “);
}
}
}
}

 

Output of List Even Numbers Java Example would be
Printing Even numbers between 1 and 50
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50

Program2 – Factorial of a number

 

/*
This program shows how to calculate
Factorial of a number.
*/
public class NumberFactorial {
public static void main(String[] args) {
int number = 5;
/*
* Factorial of any number is! n.
* For example, factorial of 4 is 4*3*2*1.
*/
int factorial = number;
for(int i =(number – 1); i > 1; i–)
4
{
factorial = factorial * i;
}
System.out.println(“Factorial of a number is ” + factorial);
}
}

 

Output of the Factorial program would be
Factorial of a number is 120

 

Program3 – Compare Two Numbers using else-if

 

/*
Compare Two Numbers Java Example
This Compare Two Numbers Java Example shows how to compare two numbers
using if else if statements.
*/
public class CompareTwoNumbers {
public static void main(String[] args) {
//declare two numbers to compare
int num1 = 324;
int num2 = 234;
if(num1 > num2){
System.out.println(num1 + ” is greater than ” + num2);
}
else if(num1 < num2){
5
System.out.println(num1 + ” is less than ” + num2);
}
else{
System.out.println(num1 + ” is equal to ” + num2);
}
}
}

 

/*
Output of Compare Two Numbers Java Example would be
324 is greater than 234
*/

 

Program4 – Determine If Year Is Leap Year

 
 

/*
Determine If Year Is Leap Year Java Example
This Determine If Year Is Leap Year Java Example shows how to
determine whether the given year is leap year or not.
*/
public class DetermineLeapYearExample {
public static void main(String[] args) {
//year we want to check
int year = 2004;
//if year is divisible by 4, it is a leap year
if(year % 400 == 0) || ((year % 4 == 0) && (year % 100 != 0))
System.out.println(“Year ” + year + ” is a leap year”);
else
System.out.println(“Year ” + year + ” is not a leap year”);
}
}

 

/*
Output of the example would be
Year 2004 is a leap year
*/

 

Program5 – Fibonacci Series

 

/* Fibonacci Series Java Example
This Fibonacci Series Java Example shows how to create and print
Fibonacci Series using Java.
*/
public class JavaFibonacciSeriesExample {
public static void main(String[] args) {
//number of elements to generate in a series
int limit = 20;
long[] series = new long[limit];
//create first 2 series elements
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series[0] = 0;
series[1] = 1;
//create the Fibonacci series and store it in an array
for(int i=2; i < limit; i++){
series[i] = series[i-1] + series[i-2];
}
//print the Fibonacci series numbers
System.out.println(“Fibonacci Series upto ” + limit);
for(int i=0; i< limit; i++){
System.out.print(series[i] + ” “);
}
}
}

 

/*
Output of the Fibonacci Series Java Example would be
Fibonacci Series upto 20
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181
*/

 

Program6 – Palindrome Number

 

/*
This program shows how to check for in the given list of numbers
whether each number is palindrome or not
*/
public class JavaPalindromeNumberExample {
public static void main(String[] args) {
//array of numbers to be checked
int numbers[] = new int[]{121,13,34,11,22,54};
//iterate through the numbers
for(int i=0; i < numbers.length; i++){
int number = numbers[i];
int reversedNumber = 0;
int temp=0;
/*
* If the number is equal to it’s reversed number, then
* the given number is a palindrome number.
*
* For ex,121 is a palindrome number while 12 is not.
*/
//reverse the number
while(number > 0){
temp = number % 10;
number = number / 10;
reversedNumber = reversedNumber * 10 + temp;
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}
if(numbers[i] == reversedNumber)
System.out.println(numbers[i] + ” is a palindrome”);
else
System.out.println(numbers[i] + ” not a palindrome “);
}
}
}

 

/*
Output of Java Palindrome Number Example would be
121 is a palindrome number
13 is not a palindrome number
34 is not a palindrome number
11 is a palindrome number
22 is a palindrome number
54 is not a palindrome number
*/

 

Program7- Generate prime numbers between 1 & given number

 

/*
Prime Numbers Java Example
This Prime Numbers Java example shows how to generate prime numbers
between 1 and given number using for loop.
*/
public class GeneratePrimeNumbersExample {
public static void main(String[] args) {
//define limit
int limit = 100;
System.out.println(“Prime numbers between 1 and ” + limit);
//loop through the numbers one by one
for(int i=1; i < 100; i++){
boolean isPrime = true;
//check to see if the number is prime
for(int j=2; j < i ; j++){
if(i % j == 0){
isPrime = false;
break;
}
}
// print the number
if(isPrime)
System.out.print(i + ” “);
}
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}
}

 

/*
Output of Prime Numbers example would be
Prime numbers between 1 and 100
1 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
*/

 

Program8- Pyramid of stars using nested for loops

 

/*
Java Pyramid 1 Example
This Java Pyramid example shows how to generate pyramid or triangle
like given below using for loop.
*
**
***
****
*****
*/
public class JavaPyramid1 {
public static void main(String[] args) {
for(int i=1; i<= 5 ;i++){
for(int j=0; j < i; j++){
System.out.print(“*”);
}
//generate a new line
System.out.println(“”);
}
}
}

 

/*
Output of the above program would be
*
**
***
****
*****
*/

 

Program9 – Reversed pyramid using for loops & decrement operator.

 

/*
10
Java Pyramid 5 Example
This Java Pyramid example shows how to generate pyramid or triangle
like given below using for loop.
12345
1234
123
12
1
*/
public class JavaPyramid5 {
public static void main(String[] args) {
for(int i=5; i>0 ;i–){
for(int j=0; j < i; j++){
System.out.print(j+1);
}
System.out.println(“”);
}
}
}

 

/*
Output of the example would be
12345
1234
123
12
1
*/

Program10 – Nested Switch

 

/*
Statements Example
This example shows how to use nested switch statements in a
java program.
*/
public class NestedSwitchExample {
public static void main(String[] args) {
/*
* Like any other Java statements, switch statements
* can also be nested in each other as given in
* below example.
*/
int i = 0;
int j = 1;
switch(i)
{
case 0:
switch(j)
{
case 0:
System.out.println(“i is 0, j is 0”);
break;
case 1:
System.out.println(“i is 0, j is 1”);
break;
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default:
System.out.println(“nested default
case!!”);
}
break;
default:
System.out.println(“No matching case found!!”);
}
}
}

 

/*
Output would be,
i is 0, j is 1
*/

Program11 – Calculate Circle Area using radius

 

/*
This program shows how to calculate
area of circle using it’s radius.
*/
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class CalculateCircleAreaExample {
public static void main(String[] args) {
int radius = 0;
System.out.println(“Please enter radius of a circle”);
try
{
//get the radius from console
BufferedReader br = new BufferedReader(new
InputStreamReader(System.in));
radius = Integer.parseInt(br.readLine());
}
//if invalid value was entered
catch(NumberFormatException ne)
{
System.out.println(“Invalid radius value” + ne);
System.exit(0);
}
catch(IOException ioe)
{
System.out.println(“IO Error :” + ioe);
System.exit(0);
}

 

/*
* Area of a circle is
* pi * r * r
* where r is a radius of a circle.
*/

//NOTE : use Math.PI constant to get value of pi double area = Math.PI * radius * radius;
System.out.println(“Area of a circle is ” + area);
}
}
/*
Output of Calculate Circle Area using Java Example would be
14
Please enter radius of a circle
19
Area of a circle is 1134.1149479459152
*/

Program12 – Factorial of a number using recursion

 

/*
This program shows how to calculate
Factorial of a number using recursion function.
*/
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class JavaFactorialUsingRecursion {
public static void main(String args[]) throws NumberFormatException,
IOException{
System.out.println(“Enter the number: “);
//get input from the user
BufferedReader br=new BufferedReader(new
InputStreamReader(System.in));
int a = Integer.parseInt(br.readLine());
//call the recursive function to generate factorial
int result= fact(a);
System.out.println(“Factorial of the number is: ” + result);
}
static int fact(int b)
{
if(b <= 1)
//if the number is 1 then return 1
return 1;
else
//else call the same function with the value – 1
return b * fact(b-1);
}
}

 

/*
Output of this Java example would be
Enter the number:
5
Factorial of the number is: 120
*/

Program13 – pyramid of numbers using for loops
/*
Generate Pyramid For a Given Number Example
This Java example shows how to generate a pyramid of numbers for given
number using for loop example.
*/
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class GeneratePyramidExample {
public static void main (String[] args) throws Exception{
BufferedReader keyboard = new BufferedReader (new
InputStreamReader(System.in));
System.out.println(“Enter Number:”);
int as= Integer.parseInt (keyboard.readLine());
System.out.println(“Enter X:”);
int x= Integer.parseInt (keyboard.readLine());
int y = 0;
for(int i=0; i<= as ;i++){
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for(int j=1; j <= i ; j++){
System.out.print(y + “\t”);
y = y + x;
}
System.out.println(“”);
}
}
}
/*
Output of this example would be
Enter Number:
5
Enter X:
1
1 2
3 4 5
6 7 8 9
10 11 12 13 14
———————————————-
17
Enter Number:
5
Enter X:
2
2 4
6 8 10
12 14 16 18
20 22 24 26 28
———————————————-
Enter Number:
5
Enter X:
3
3 6
9 12 15
18 21 24 27
30 33 36 39 42
*/
18
Program14 – To Find Maximum of Two Numbers.
/*
To Find Maximum of 2 Numbers using if else
*/
class Maxoftwo{
public static void main(String args[]){
//taking value as command line argument.
//Converting String format to Integer value
int i = Integer.parseInt(args[0]);
int j = Integer.parseInt(args[1]);
if(i > j)
System.out.println(i+” is greater than “+j);
else
System.out.println(j+” is greater than “+i);
}
}
Program15 – To Find Minimum of Two Numbers using
conditional operator
/*
To find minimum of 2 Numbers using ternary operator
*/
class Minoftwo{
public static void main(String args[]){
//taking value as command line argument.
//Converting String format to Integer value
int i = Integer.parseInt(args[0]);
19
int j = Integer.parseInt(args[1]);
int result = (i<j)?i:j;
System.out.println(result+” is a minimum value”);
}
}
20
Program 16
/* Write a program that will read a float type value from the keyboard and
print the following output.
->Small Integer not less than the number.
->Given Number.
->Largest Integer not greater than the number.
*/
class ValueFormat{
public static void main(String args[]){
double i = 34.32; //given number
System.out.println(“Small Integer not greater than the number :
“+Math.ceil(i));
System.out.println(“Given Number : “+i);
System.out.println(“Largest Integer not greater than the number :
“+Math.floor(i));
}
Program 17 – Write a program to generate 5 Random nos.
between 1 to 100, and it should not follow with decimal
point.
class RandomDemo{
public static void main(String args[]){
for(int i=1;i<=5;i++){
System.out.println((int)(Math.random()*100));
}
}
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}
Program 18 – Write a program to display a greet message
according to Marks obtained by student.
class SwitchDemo{
public static void main(String args[]){
int marks = Integer.parseInt(args[0]); //take marks
as command line argument.
switch(marks/10){
case 10:
case 9:
case 8:
System.out.println(“Excellent”);
break;
case 7:
System.out.println(“Very Good”);
break;
case 6:
System.out.println(“Good”);
break;
case 5:
System.out.println(“Work Hard”);
break;
case 4:
System.out.println(“Poor”);
break;
case 3:
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case 2:
case 1:
case 0:
System.out.println(“Very Poor”);
break;
default:
System.out.println(“Invalid value Entered”);
}
}
}
Program 19 – Write a program to find SUM AND PRODUCT of
a given Digit.
class Sum_Product_ofDigit{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
//taking value as command line argument.
int temp = num,result=0;
//Logic for sum of digit
while(temp>0){
result = result + temp;
temp–;
}
System.out.println(“Sum of Digit for “+num+” is : “+result);
//Logic for product of digit
temp = num;
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result = 1;
while(temp > 0){
result = result * temp;
temp–;
}
System.out.println(“Product of Digit for “+num+” is : “+result);
}
}
Program 20 – Write a program to find sum of all
integers greater than 100 and less than 200 that are
divisible by 7
class SumOfDigit{
public static void main(String args[]){
int result=0;
for(int i=100;i<=200;i++){
if(i%7==0)
result+=i;
}
System.out.println(“Output of Program is : “+result);
}
}
Program 21 – Write a program to concatenate string
using for Loop
Example:
Input – 5
24
Output – 1 2 3 4 5 */
class Join{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
String result = ” “;
for(int i=1;i<=num;i++){
result = result + i + ” “;
}
System.out.println(result);
}
}
Program 22 – Program to Display Multiplication Table
class MultiplicationTable{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
System.out.println(“*****MULTIPLICATION TABLE*****”);
for(int i=1;i<=num;i++){
for(int j=1;j<=num;j++){
System.out.print(” “+i*j+” “);
}
System.out.print(“\n”);
}
}
}
25
Program 23 – Write a program to Swap the values
class Swap{
public static void main(String args[]){
int num1 = Integer.parseInt(args[0]);
int num2 = Integer.parseInt(args[1]);
System.out.println(“\n***Before Swapping***”);
System.out.println(“Number 1 : “+num1);
System.out.println(“Number 2 : “+num2);
//Swap logic
num1 = num1 + num2;
num2 = num1 – num2;
num1 = num1 – num2;
System.out.println(“\n***After Swapping***”);
System.out.println(“Number 1 : “+num1);
System.out.println(“Number 2 : “+num2);
}
}
26
Program 24 – Write a program to convert given no. of
days into months and days.(Assume that each month is of
30 days)
Example :
Input – 69
Output – 69 days = 2 Month and 9 days */
class DayMonthDemo{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int days = num%30;
int month = num/30;
System.out.println(num+” days = “+month+” Month and “+days+” days”);
}
}
Program 25 – Write a program to Display Invert Triangle
using while loop.
Example:
Input – 5
Output :
5 5 5 5 5
4 4 4 4
3 3 3
2 2
1
27
*/
class InvertTriangle{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
while(num > 0){
for(int j=1;j<=num;j++){
System.out.print(” “+num+” “);
}
System.out.print(“\n”);
num–;
}
}
}
Program 26 – Write a program to find whether given no.
is Armstrong or not.
Example :
Input – 153
Output – 1^3 + 5^3 + 3^3 = 153, so it is Armstrong no. */
class Armstrong{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int n = num; //use to check at last time
int check=0,remainder;
while(num > 0){
remainder = num % 10;
28
check = check + (int)Math.pow(remainder,3);
num = num / 10;
}
if(check == n)
System.out.println(n+” is an Armstrong Number”);
else
System.out.println(n+” is not a Armstrong Number”);
}
}
Program 27 – switch case demo
Example :
Input – 124
Output – One Two Four */
class SwitchCaseDemo{
public static void main(String args[]){
try{
int num = Integer.parseInt(args[0]);
int n = num; //used at last time check
int reverse=0,remainder;
while(num > 0){
remainder = num % 10;
reverse = reverse * 10 + remainder;
num = num / 10;
}
29
String result=””; //contains the actual output
while(reverse > 0){
remainder = reverse % 10;
reverse = reverse / 10;
switch(remainder){
case 0 :
result = result + “Zero “;
break;
case 1 :
result = result + “One “;
break;
case 2 :
result = result + “Two “;
break;
case 3 :
result = result + “Three “;
break;
case 4 :
result = result + “Four “;
break;
case 5 :
result = result + “Five “;
break;
case 6 :
result = result + “Six “;
break;
30
case 7 :
result = result + “Seven “;
break;
case 8 :
result = result + “Eight “;
break;
case 9 :
result = result + “Nine “;
break;
default:
result=””;
}
}
System.out.println(result);
}catch(Exception e){
System.out.println(“Invalid Number Format”);
}
}
}
Program 28 – Write a program to generate Harmonic
Series.
Example :
Input – 5
Output – 1 + 1/2 + 1/3 + 1/4 + 1/5 = 2.28 (Approximately) */
class HarmonicSeries{
31
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
double result = 0.0;
while(num > 0){
result = result + (double) 1 / num;
num–;
}
System.out.println(“Output of Harmonic Series is “+result);
}
}
32
Program 29 – Write a program to find average of
consecutive N Odd no. and Even no.
class EvenOdd_Avg{
public static void main(String args[]){
int n = Integer.parseInt(args[0]);
int cntEven=0,cntOdd=0,sumEven=0,sumOdd=0;
while(n > 0){
if(n%2==0){
cntEven++;
sumEven = sumEven + n;
}
else{
cntOdd++;
sumOdd = sumOdd + n;
}
n–;
}
int evenAvg,oddAvg;
evenAvg = sumEven/cntEven;
oddAvg = sumOdd/cntOdd;
System.out.println(“Average of first N Even no is “+evenAvg);
System.out.println(“Average of first N Odd no is “+oddAvg);
}
}
33
Program 30 – Display Triangle as follow.
1
2 3
4 5 6
7 8 9 10 … N */
class Output1{
public static void main(String args[]){
int c=0;
int n = Integer.parseInt(args[0]);
loop1: for(int i=1;i<=n;i++){
loop2: for(int j=1;j<=i;j++){
if(c!=n){
c++;
System.out.print(c+” “);
}
else
break loop1;
}
System.out.print(“\n”);
}
}
}
34
Extra Programs 1 – Write a program to Find whether
number is Prime or Not.
class PrimeNo{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int flag=0;
for(int i=2;i<num;i++){
if(num%i==0)
{
System.out.println(num+” is not a Prime Number”);
flag = 1;
break;
}
}
if(flag==0)
System.out.println(num+” is a Prime Number”);
}
}
35
Program 2 – Write a program to find whether no. is
palindrome or not.
Example :
Input – 12521 is a palindrome no.
Input – 12345 is not a palindrome no. */
class Palindrome{
public static void main(String args[]){
int num = Integer.parseInt(args[0]);
int n = num; //used at last time check
int reverse=0,remainder;
while(num > 0){
remainder = num % 10;
reverse = reverse * 10 + remainder;
num = num / 10;
}
if(reverse == n)
System.out.println(n+” is a Palindrome Number”);
else
System.out.println(n+” is not a Palindrome Number”);
}
}
36
Program 3 – Display Triangle as follow
1 0
1 0 1
0 1 0 1 */
class Output2{
public static void main(String args[]){
for(int i=1;i<=4;i++){
for(int j=1;j<=i;j++){
System.out.print(((i+j)%2)+” “);
}
System.out.print(“\n”);
}
}
}
37