Techpils: Interview

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Java Programs for Practice

2. Write a program to generate a following @'s triangle:

3. Write a Java program to print the following triangle:

4. Write a Java program to display the following rhombus symbol structure:

5. Write a Java program to display the following number rhombus structure:

6. Write a Java program to print the following number pyramid:

7. Write a Java program to display the following character rhombus structure:

Character pattern pyramid program in Java

package demo;
import java.util.Scanner;
public class CharacterPattern
{
public static void main(String[] args)
{
char ch, r, c;
System.out.println("Enter last pyramid character : ");
Scanner sc = new Scanner(System.in);
ch = sc.next().charAt(0);
if (ch >= 'a' && ch <= 'z') {
ch = (char)(ch - 32);
}
for (r = 'A'; r <= ch; r++) {
for (c = 'A'; c <= r; c++) {
System.out.print(r + "" + (char)(r + 32) + " ");
}
System.out.println();
}
}
}

Output:

Enter last pyramid character :
e

Aa
Bb Bb
Cc Cc Cc
Dd Dd Dd Dd
Ee Ee Ee Ee Ee

BUILD SUCCESSFUL (total time: 7 seconds)

Java Program for Reverse Floyd Triangle - Half Floyd number diamond

package demo;
public class FloydTriangle
{
public static void main(String[] args)
{
  int num = 4, y;
y = num + 1;
  for (int r = 1; r <= num; r++, y--) {
for (int c = 1, n = num; c <= r; c++, n--) {
System.out.print(" " + n);
}
for (int c = 1, p = y; c < r; c++, p++) {
System.out.print(" " + p);
}
System.out.println();
}
  for (int r = num - 1, x = 1; r >= 1; r--, x--) {
for (int c = r, n = num; c >= 1; c--, n--) {
System.out.print(" " + n);
}
for (int c = r, z = num - x; c > 1; c--, z++) {
System.out.print(" " + z);
}
System.out.println();
}
}
}

Output:

4
4 3 4
4 3 2 3 4
4 3 2 1 2 3 4
4 3 2 3 4
4 3 4
4

BUILD SUCCESSFUL (total time: 1 second)

Java Program for Number Pattern of Half Diamond.

package demo;
import java.util.Scanner;
public class HalfDaimond
{
public static void main(String[] args)
{
int num, q;
Scanner sc = new Scanner(System.in);
System.out.print("Enter Seeding Number : ");
num = sc.nextInt();
for (int r = 1, n = num; r <= num; r++, n--) {
for (int c = r, p = n; c >= 1; c--, p++) {
System.out.print(p);
}
for (int c = r, p = num - 1; c > 1; c--, p--) {
System.out.print(p);
}
System.out.println();
}
for (int r = 1; r < num; r++) {
for (int c = r, p = r + 1; c < num; c++, p++) {
System.out.print(p);
}
for (int c = num - r, p = num - 1; c > 1; c--, p--) {
System.out.print(p);
}
System.out.println();
}
}
}

Output:

Enter Seeding Number : 4

4
343
23432
1234321
23432
343
4

BUILD SUCCESSFUL (total time: 3 seconds)

Java program to split number into digits.

package demo;
import java.util.Scanner;
public class SplitNumber
{
public static void main(String[] args)
{
int num, temp, factor = 1;
Scanner sc = new Scanner(System.in);
System.out.println("Enter a number: ");
num = sc.nextInt();
temp = num;
while (temp != 0) {
temp = temp / 10;
factor = factor * 10;
}
System.out.print("Each digits of given number are: ");
while (factor > 1) {
factor = factor / 10;
System.out.print((num / factor) + " ");
num = num % factor;
}
}
}

Output:
Enter a number: 4732
Each digits of given number are: 4 7 3 2
BUILD SUCCESSFUL (total time: 21 seconds)

Java program for octal to decimal.

package demo;
import java.util.Scanner;
public class OctalToDecimal
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
long octal, decimal = 0;
int i = 0;
System.out.print("Enter any octal number: ");
octal = sc.nextLong();
while (octal != 0)
{
decimal = (long)(decimal + (octal % 10) * Math.pow(8, i++));
octal = octal / 10;
}
System.out.print("Equivalent decimal value: " + decimal);
}
}

Output:
Enter any octal number: 1000
Equivalent decimal value: 512
BUILD SUCCESSFUL (total time: 3 seconds)

Java program to reverse a String without using direct method.

import java.io.BufferedReader;
public class ReverseOfString {
public static String reverseString(String s)
{
int l = s.length();
String backward = "";
for (int i = l - 1; i >= 0; i--)
{
backward = backward + s.charAt(i);
}
return backward;
}
public static void main(String args[]) {
String backwards = reverseString("Umesh Kushwaha");
System.out.println("Reverse String is " + backwards);
}
}

Output:
Reverse String is ahawhsuK hsemU

Java program to accept a string and print each character of the string along with its ASCII code.

class CalculateAscii {
public static void main(String args[]) {
word("Umesh Kushwaha");
}
static void word(String s) {
int len = s.length();
int a;
char a1;
for (int i = 0; i < len; i++) {
a1 = s.charAt(i);
a = a1;
System.out.println(a1 + "–>" + a);
}
}
}

Output:

U–>85
m–>109
e–>101
s–>115
h–>104
–>32
K–>75
u–>117
s–>115
h–>104
w–>119
a–>97
h–>104
a–>97

Java program to calculate 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());
int result = fact(a); //call the recursive function to generate factorial
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
*/

Java program to 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) {
int limit = 100;   //define limit
System.out.println("Prime numbers between 1 and " + limit);
for (int i = 1; i < 100; i++) { //loop through the numbers one by one
boolean isPrime = true;
for (int j = 2; j < i; j++) { //check to see if the number is prime
if (i % j == 0) {
isPrime = false;
break;
}
}   // print the number
if (isPrime)
System.out.print(i + " ");
}
}
}

/*
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
*/

Java program to check 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) {
int numbers[] = new int[] {121,13,34,11,22,54};
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;
}
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
*/

Java program to design a class account using the inheritance and static that show all function of bank and generate account number dyanamically.

import java.util.*;
class Bank {
static int acc_no = 10001;
float amt;
public void display() {
System.out.println("Account no :" + acc_no);
System.out.println("Current Amount :" + amt);
}
public bank() {
amt = 1000;
System.out.println("Ur account no is " + acc_no);
acc_no++;
}
public void getamt() {
System.out.println("Current balance :" + amt);
}
public void withdraw(float x) {
if (amt == 1000 || amt <= x) {
System.out.println("Sorry u can't withdraw");
} else {
amt = amt - x;
System.out.println("amount withdrawn :" + x);
System.out.println("After withdrawl");
getamt();
}
}
public void deposit(float x) {
if (x == 0.0)
System.out.println("OOPS 0 can't be deposited");
else {
amt += x;
System.out.println("After deposition");
getamt();
}
}
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
bank b1 = new bank();
b1.deposit(0);
b1.withdraw(120.5 f);
b1.display();
System.out.println("\n");
bank b2 = new bank();
b2.deposit(1000.0 f);
b2.withdraw(150.5 f);
}
}

Java program to calculate the Simple Interest and Input by the user.

import java.util.*;
class SimpleInterest {
int p, t;
float si, r;
public si() {
r = 0;
p = 0;
}
public void getdata() {
Scanner sc = new Scanner(System.in);
System.out.println("Enter principle : ");
p = sc.nextInt();
System.out.println("Enter rate : ");
r = sc.nextFloat();
System.out.println("Enter time period : ");
t = sc.nextInt();
}
public void cal() {
si = (p * r * t) / 100;
}
public void display() {
System.out.println("Principle : Rs" + p);
System.out.println("Rate : " + r);
System.out.println("Time period : " + t);
System.out.println("Simple Interest : Rs" + si);
}
public static void main(String args[]) {
si s = new si();
s.getdata();
s.cal();
s.display();
}
}

Java program to test the Prime number.

import java.util.*;
class Prime {
public static void main(String args[]) {
int flag, x, i;
flag = 0;
int a[] = new int[7];
for (x = 0; x < args.length; x++) {
a[x] = Integer.parseInt(args[x]);
for (i = 2; i < (a[x] / 2); i++) {
if ((a[x] % i) == 0) {
break;
} else flag = 1;
}
if (flag == 1)
System.out.println(a[x] + " is a prime no ");
else
System.out.println(a[x] + " is not a prime no ");
flag = 0;
}
}
}

Java program to Demonstrate Type Casting.

class Typecast {
public static void main(String args[]) {
byte h = 127;
int a = 300;
float a1 = 12.222 f;
float g;
short b = 200;
long c = 999999;
float e = 345.89 F;
double f = 45645.78222222222222;
g = (float) f;
System.out.println("short b =" + g);
System.out.println("short b =" + b);
System.out.println("long c =" + c);
System.out.println("float e=" + e);
System.out.println("double f=" + f);
System.out.println("short b=" + b);
System.out.println("short to byte " + (byte) b);
System.out.println("int to byte " + (byte) a);
System.out.println("int to float" + (float) a);
System.out.println("long to byte " + (byte) c);
System.out.println("double to long " + (long) f);
System.out.println("double to int " + (int) f);
System.out.println("double to byte " + (byte) f);
System.out.println("double to short " + (short) f);
System.out.println("double to float " + (float) f);
System.out.println("float to int " + (int) e);
System.out.println("float to byte " + (byte) e);
System.out.println("float to short " + (short) e);
System.out.println("float to long " + (long) e);
System.out.println("float to double =" + (double) e);
System.out.println("long to int" + (int) c);
System.out.println("byte to int =" + (int) h);
}
}

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