JavaKing: Interview Question

import java.util.Scanner;
public class Series
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println("Enter the no of terms ");
int n = sc.nextInt();
double sum = 0;
for (int i = 1; i <= n; i++)
sum = sum + (double) 1 / Math.pow(i, 2);
System.out.println("Sum of series = " + sum);
}
}

Output:
Enter the no of terms
5
Sum of series = 1.4636111111111112
BUILD SUCCESSFUL (total time: 2 seconds)

import java.util.Scanner;
public class Series
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.println("Enter the no of terms ");
int n = sc.nextInt();
int sum = 0, i = 0;
for (int j = 1; j <= n; j++)
{
for (i = 1; i <= j; i++)
{
sum = sum + i;
}
i = 1;
}
System.out.println("Sum of series = " + sum);
}
}

Output:
Enter the no of terms
4
Sum of series = 20
BUILD SUCCESSFUL (total time: 2 seconds)

import java.util.Scanner;
public class Series
{
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
double sum = 0;
System.out.println("Enter the no of terms ");
int n = sc.nextInt();
for (int i = 1; i <= n; i++)
{
if (i % 2 == 0) {
sum = sum - (double) 1 / (i * i * i);
} else {
sum = sum + (double) 1 / (i * i * i);
}
}
System.out.println(" Sum of the series : " + sum);
}
}

Output:

Enter the no of terms
5
Sum of the series : 0.904412037037037
BUILD SUCCESSFUL (total time: 3 seconds)

import java.util.Scanner;
public class Series
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of terms: ");
int n = sc.nextInt();
int s = 0, c; // s for terms of series, c for n terms
for (c = 1; c <= n; c++) // To generate n terms
{
s = s * 10 + 1;
System.out.print(s + " ");
} //for ends
}
}

Output:
Enter the number of terms: 7
1, 11, 111, 1111, 11111, 111111, 1111111......
BUILD SUCCESSFUL (total time: 3 seconds)

import java.util.Scanner;
public class Series
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of terms: ");
int n = sc.nextInt();
int s = 0, c; // s for terms of series, c for counter to generate n terms
for (c = 1; c <= n; c++) {
s = s * 10 + c;
System.out.print(s + " ");
}
}
}

Output:
Enter the number of terms: 6
1, 12, 123, 1234, 12345, 123456.......
BUILD SUCCESSFUL (total time: 3 seconds)

import java.util.Scanner;
public class OddSeries
{
public static void main(String args[])
{
Scanner sc = new Scanner(System.in);
System.out.print("Enter the number of terms: ");
int n = sc.nextInt();
int i = 1, c, f = 1; // i for odd nos, c for counter, f for flag
for (c = 1; c <= n; c++) {
if (f % 2 == 0) {
System.out.print(-i + " ");
} else {
System.out.print(i + " ");
}
i += 2;
f++;
} //Loop ends
}
}

Output:

Enter the number of terms: 6
1 -3 5 -7 9 -11......
BUILD SUCCESSFUL (total time: 6 seconds)

import java.util.Scanner;
public class Series
{
public static void main(String args[]) {
Scanner sc = new Scanner(System.in);
int c, i = 2, n; // c for counter, i for even nos.
System.out.print("Enter the number of terms: ");
n = sc.nextInt();
System.out.print("\n");
for (c = 1; c <= n; c++, i += 2) //to generate n terms of the series
{
if (i % 4 == 0) {
System.out.print(-i + " ");
} else {
System.out.print(i + " ");
}
}
}
}

Output:

Enter the number of terms: 10
2 -4 6 -8 10 -12 14 -16 18 -20
BUILD SUCCESSFUL (total time: 6 seconds)

A tribonacci series is one in which the sum next term is the sum of previous three terms
Example 0 1 2 3 6 11 20………….

import java.util.Scanner;

public class Tribonacci

{

public static void main(String args[]) {

func(10);

}

static void func(int n) {

int a = 0, b = 1, c = 2, d = 0, i;

System.out.print(a + " , " + b + " , " + c);

for (i = 4; i <= n; i++) {

d = a + b + c;

System.out.print(", " + d);

a = b;

b = c;

c = d;

}

Output:

0 , 1 , 2, 3, 6, 11, 20, 37, 68, 125

BUILD SUCCESSFUL (total time: 1 second)

A fibonacci series is one in which the next term is the sum of previous two terms
Example. 0 1 1 2 3 5 8……

import java.util.Scanner;
public class Fibonacci
{
public static void main(String args[]) {
func(10);
}
static void func(int n) {
int a = 0, b = 1, c = 0, i;
System.out.print(a + " , " + b);
for (i = 3; i <= n; i++) {
c = a + b;
System.out.print(", " + c);
a = b;
b = c;
}
}
}

Output:

0 , 1, 1, 2, 3, 5, 8, 13, 21, 34
BUILD SUCCESSFUL (total time: 0 seconds)

import java.util.Scanner;
public class WordFrequencyCounter {
public static void main(String args[]) {
Scanner scan = new Scanner(System.in);
System.out.println("enter main string");
String s = scan.nextLine();
System.out.println("enter string to be searched");
String f = scan.nextLine();
s = s + " ";
int l = s.length();
char a;
int c = 0;
String s1 = "";
for (int i = 0; i < l; i++) {
a = s.charAt(i);
if (a != ' ') {
s1 = s1 + a;
} else {
if (s1.equalsIgnoreCase(f) == true) {
c++;
}
s1 = "";
}
}
System.out.println("Frequency of the word " + f + " is " + c);
}
}

Output:
Enter main string
Umesh Kumar Kushwaha Kumar
enter string to be searched
Kumar
Frequency of the word Kumar is 2

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class RemoveVowels
{
public static void main(String args[]) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String str1, str2 = "";
char ch, ch1;
int i, len;
System.out.println("Enter the Sentence:");
str1 = br.readLine();
len = str1.length();
for (i = 0; i < len; i++) {
ch = str1.charAt(i);
ch1 = Character.toLowerCase(ch);
switch (ch1) {
case 'a':
case 'e':
case 'i':
case 'o':
case 'u':
break;
default:
str2 = str2 + ch;
} //switch ends
} //for ends
System.out.println("Modified string without vowels:" + str2);
} //method ends
}

Output:
Enter the Sentence:
umesh kumar kushwaha
Modified string without vowels:msh kmr kshwh

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class RemoveCommonDuplicateChar
{
public static void main(String args[]) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String s1, s2, s3 = "", s4 = "";
int a[], b[], x = 0, y = 0;
int len1, len2;
char ch;
int i, j;
System.out.println("Enter the first sentence:");
s1 = br.readLine().trim();
System.out.println("Enter the second sentence:");
s2 = br.readLine().trim();
len1 = s1.length();
len2 = s2.length();
a = new int[len1];
b = new int[len2];
for (i = 0; i < len1; i++) {
ch = s1.charAt(i);
for (j = 0; j < len2; j++) {
if (ch == s2.charAt(j)) {
break;
}
}
if (j != len2) {
a[x++] = i;
b[y++] = j;
}
}
for (i = 0; i < len1; i++) {
for (j = 0; j < x; j++) {
if (i == a[j]) {
break;
}
}
if (j == x) {
s3 = s3 + s1.charAt(i);
}
}
for (i = 0; i < len2; i++) {
for (j = 0; j < y; j++) {
if (i == b[j]) {
break;
}
}
if (j == y) {
s4 = s4 + s2.charAt(i);
}
}
System.out.println("Original string1=" + s1 + " Modified string1=" + s3);
System.out.println("Original string2=" + s2 + " Modified string2=" + s4);
}
}

Output:

Enter the first sentence:
Umesh Kumar Kushwaha
Enter the second sentence:
Rahul Kumar Singh
Original string1=Umesh Kumar Kushwaha Modified string1=Uessw
Original string2=Rahul Kumar Singh Modified string2=Rlua Singh

import java.io.BufferedReader;
class FindMinMaxString {
public static void main(String args[]) {
findMethod("My name is Umesh Kushwaha");
}
static public void findMethod(String s) {
String str = s + " ";
char ch = ' ';
int len = str.length(), l = 0;
int min = len, max = 0;
String shortest_word = "", longest_word = "", word = "";
for (int i = 0; i < len; i++) {
ch = str.charAt(i);
if (ch != ' ') {
word += ch;
} //if ends
else {
l = word.length();
if (l < min) {
min = l;
shortest_word = word;
} //if ends
if (l > max) {
max = l;
longest_word = word;
}
word = "";
}
}
System.out.println("Shortest word = " + shortest_word + " with length " + min);
System.out.println("Longest word = " + longest_word + " with length " + max);
}
}

Output:
Shortest word = My with length 2
Longest word = Kushwaha with length 8

Example.

Enter your name
Umesh Kumar Kushwaha
Initials are U.K.K.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
class InitialName {
public static void main(String args[]) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter your name");
String s = br.readLine(), s1 = "";
s = " " + s;
int len = s.length();
char a;
for (int i = 0; i < len; i++) {
a = s.charAt(i);
if (a == ' ') {
s1 = s1 + s.charAt(i + 1) + ".";
}
}
System.out.println("Initials are " + s1);
}
}

Output:
Enter your name
Umesh Kumar Kushwaha
Initials are U.K.K.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.logging.Level;
import java.util.logging.Logger;

class CountFrequencyOfWord {
public static void main(String args[]) {
try {
input();
} catch (IOException ex) {
Logger.getLogger(CountFrequencyOfWord .class.getName()).log(Level.SEVERE, null, ex);
}
}
static void input() throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter a sentence");
String s = br.readLine();
System.out.println("Enter the letter ");
char a = (char) br.read();
int len = s.length();
int c = 0;
char x;
for (int i = 0; i < len; i++) {
x = Character.toLowerCase(s.charAt(i));
if (x == a)
c = c + 1;
}
System.out.println("Frequency of the letter " + a + " in the sentence " + s + " is " + c);
}
}

Output:

Enter a sentence
Hi my name is umesh
Enter the letter
m
Frequency of the letter m in the sentence "Hi my name is umesh" is 3

class RemoveDuplicate {
public static void main(String args[]) {
remove("123aa bbbcc c2589 99oppq rtyyy");
}
static void remove(String s) {
int l = s.length();
int c;
String org = s, s1 = "";
for (int i = 0; i < (l - 1); i++) {
s1 = s.substring(0, i + 1);
c = 0;
for (int j = i + 1; j < l; j++) {
if (s.charAt(i) == s.charAt(j)) {
c++;
continue;
} else
s1 = s1 + s.charAt(j);
}
s = s1;
s1 = "";
if (c > 0)
l -= c;
}
System.out.println("Original String:" + org);
System.out.println("String after removing duplicates: " + s);
}
}

Output:

Original String:123aa bbbcc c2589 99oppq rtyyy

String after removing duplicates: 123a bc589opqrty

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);
}
}

import java.util.*;
class Average {
public static void main(String args[]) {
Scanner sc = new Scanner(System.in); // to take user input
int choice;
int a = 0, min = 0, max = 0, x;
int n = args.length;
System.out.println("1-sum");
System.out.println("2-Average");
System.out.println("3-Minimum");
System.out.println("4-Maximum");
System.out.println("Enter Ur Choice : ");
choice = sc.nextInt();
for (int i = 0; i < n; i++) {
a += Integer.parseInt(args[i]); //to convert string into Integer
}
switch (choice) {
case 1:
System.out.println("The sum is : " + a);
break;
case 2:
System.out.println("The Average is : " + a / n);
break;
case 3:
for (int i = 0; i < n - 1; i++) {
x = Integer.parseInt(args[i]);
if (x < Integer.parseInt(args[i + 1]))
min = x;
else min = Integer.parseInt(args[i + 1]);
}
System.out.println("The minimum is : " + min);
break;
case 4:
for (int i = 0; i < n - 1; i++) {
x = Integer.parseInt(args[i]);
if (x > Integer.parseInt(args[i + 1]))
max = x;
else
max = Integer.parseInt(args[i + 1]);
}
System.out.println("The maximum is : " + max);
break;
}
}
}

Product database:
create table Product
(
pid number (4),
pname varchar2 (15),
price number (6, 2)
);

web.xml:
<web-app>
<servlet>
<servlet-name>abc</servlet-name>
<servlet-class>DatabaServ</servlet-class>
</servlet>

<servlet-mapping>

<servlet-name>abc</servlet-name>

<url-pattern>/getdata</url-pattern>

</servlet-mapping>

</web-app>

DarabaServ.java:

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.*;

import java.sql.*;

public class DatabaServ extends HttpServlet {

public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {

res.setContentType("text/html");

PrintWriter pw = res.getWriter();

String pid1 = req.getParameter("prodata_pid");

String pname = req.getParameter("prodata_pname");

String price1 = req.getParameter("prodata_price");

int pid = Integer.parseInt(pid1);

float price = Float.parseFloat(price1);

try {

DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());

Connection con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:

Hanuman ","

scott ","

tiger ");

PreparedStatement ps = con.prepareStatement("insert into Product values (?,?,?)"); ps.setInt(1, pid); ps.setString(2, pname); ps.setFloat(3, price); int i = ps.executeUpdate(); pw.println("<h4>" + i + " ROWS INSERTED..."); con.close();

} catch (Exception e) {

res.sendError(503, "PROBLEM IN DATABASE...");

}

public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {

doGet(req, res);

}

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