String Handling

The trim() method of the String class removes ............... .

While using the toLowerCase() method on a string containing special characters, ............... .

The index of a string ............... .

The indexOf() method returns the position of the ............... .

The return type of the equals() method is ............... .

Which one of the given statements is true for the following statement? string1.compareTo(string2)

Which one of the given statements is true for the following statement? string1.compareTo(string2)

The valueOf() method returns the ............... .

Output of the following statement is ............... .

System.out.println("SUNDAY".substring(3));

Output of the following statement is ............... .

System.out.println("WONDERFUL".substring(3,4));

How do you create strings implicitly and explicitly?

Mention the purpose and syntax of trim() method.

Mention the purpose and syntax of length() method.

Mention the purpose and syntax of charAt() method.

Mention the purpose and syntax of indexOf() method.

Mention the purpose and syntax of lastIndexOf() method.

Mention the purpose and syntax of equals() method.

Mention the purpose and syntax of compareTo() method.

Mention the purpose and syntax of compareToIgnore() method.

Mention the purpose and syntax of substring() method.

Mention the purpose and syntax of valueOf() method.

Differentiate between equals() and compareTo().

Differentiate between equals() and == .

Differentiate between startsWith() and endsWith().

Differentiate between indexOf() and lastIndexOf().

Differentiate between compareTo() and compareToIgnore().

Write a program to input a sentence and print each word of the string along with its length in tabular form.

import java.util.Scanner;

public class KboatWordsLengthTable
{
   public static void main(String args[]) {
       Scanner in = new Scanner(System.in);
       System.out.println("Enter a sentence:");
       String str = in.nextLine();
             
       str += " ";
       int len = str.length();
       
       String word = "";
       int wLen = 0; 
       System.out.println("Word Length");
       for (int i = 0; i < len; i++) {
           char ch = str.charAt(i);
           if (ch != ' ')   {
               word = word + ch;
               wLen++;
           }
           else {
               System.out.println(word + "\t" + wLen);
               word = "";
               wLen = 0;
               
           }
       }
    }
}

Write a program to input a sentence and arrange each word of the string in alphabetical order.

import java.util.Scanner;

public class KboatWordsSort
{
   public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter a sentence:");
        String str = in.nextLine();
             
        str += " ";
        int len = str.length();
    
        String word = "";
        int wordCount = 0;
        char ch;
        // calculating no. of words
        for (int i = 0; i < len; i++) 
            if (str.charAt(i) == ' ')   
                wordCount++;
                
        String wordArr[] = new String[wordCount];
        int index = 0;
        // storing words in array
        for (int i = 0; i < len; i++) {
            ch = str.charAt(i);
            if (ch != ' ')   {
                word = word + ch;    
            }
            else {
                wordArr[index++] = word;
                word = "";
            }
        }
        //bubble sort
         for (int i = 0; i < wordCount - 1; i++) {
            for (int j = 0; j < wordCount - i - 1; j++) {
                if (wordArr[j].compareTo(wordArr[j + 1]) > 1) {
                    String t = wordArr[j];
                    wordArr[j] = wordArr[j+1];
                    wordArr[j+1] = t;
                }
            } 
        }
        // printing
        for(int i = 0; i < wordCount; i++)
            System.out.print(wordArr[i] + " ");
    }
}

Write a program to input a sentence and arrange words of the string in order of their lengths from shortest to longest.

import java.util.Scanner;

public class KboatWordsSortbyLength
{
   public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter a sentence:");
        String str = in.nextLine();
             
        str += " ";
        int len = str.length();
    
        String word = "";
        int wordCount = 0;
        char ch;
        // calculating no. of words
        for (int i = 0; i < len; i++) { 
            if (str.charAt(i) == ' ') {  
                wordCount++;
            }
        }
                
        String wordArr[] = new String[wordCount];
        int index = 0;
        // storing words in array
        for (int i = 0; i < len; i++) {
            ch = str.charAt(i);
            if (ch != ' ')   {
                word = word + ch;
                
            }
            else {
                wordArr[index++] = word;
                word = "";
            }
        }
        //bubble sort
         for (int i = 0; i < wordCount - 1; i++) {
            for (int j = 0; j < wordCount - i - 1; j++) {
                if (wordArr[j].length() > wordArr[j + 1].length()) {
                    String t = wordArr[j];
                    wordArr[j] = wordArr[j+1];
                    wordArr[j+1] = t;
                }
            } 
        }
        // printing
        for(int i = 0; i < wordCount; i++) {
            System.out.print(wordArr[i] + " ");
        }
    }
}

Write a program to input a string in uppercase and print the frequency of each character.
Sample Input : COMPUTER HARDWARE
Sample Output

Character	Frequency
A	            2
C	            1
D	            1
E	            2
H	            1
M	            1   
0	            1
p	            1
R	            1

import java.util.Scanner;

public class KboatLetterFreq
{
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter a sentence:");
        String str = in.nextLine();
        str = str.toUpperCase();
        int freqMap[] = new int[26];
        int len = str.length();
        
        for (int i = 0; i < len; i++) {
            char ch = str.charAt(i);
            if (Character.isLetter(ch)) {
                int chIdx = ch - 65;
                freqMap[chIdx]++;
            }
        }
        
        System.out.println("Character\tFrequency");
        for (int i = 0; i < freqMap.length; i++) {
            if (freqMap[i] > 0) {
                System.out.println((char)(i + 65) 
                            + "\t\t" + freqMap[i]);
            }
        }
    }
}

Write a program to input a string and print each word of the string in the reverse order.
Sample Input:
Enter a string: My name is Raman
Sample Output
yM eman si namaR

import java.util.Scanner;

public class KboatWordsReverse
{
   public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter a sentence:");
        String str = in.nextLine();
             
        str += " ";
        int len = str.length();
    
        String word = "";
        int wLen = 0;
        char ch;

        for (int i = 0; i < len; i++) {
            ch = str.charAt(i);
            if (ch != ' ')   {
                word = word + ch;  
            }
            else {
                wLen = word.length();
                for(int j = wLen - 1; j >= 0; j--) {
                    System.out.print(word.charAt(j));
                }
                System.out.print(' ');
                word = "";
            }
        } 
    }
}

Write a program in Java to accept a string and display the number of uppercase, number of lowercase, number of special characters and number of digits present in the string.

import java.util.Scanner;

public class KboatCount
{
   public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.println("Enter a sentence:");
        String str = in.nextLine();
             
        int len = str.length();
    
        int uc = 0;
        int lc = 0;
        int sc = 0;
        int dc = 0;
        char ch;

        for (int i = 0; i < len; i++) {
            ch = str.charAt(i);
            if (Character.isUpperCase(ch))  
                uc++;    
            else if (Character.isLowerCase(ch))
                lc++;
            else if (Character.isDigit(ch))
                dc++;
            else if (!Character.isWhitespace(ch))
                sc++;
        }
        
        System.out.println("UpperCase Count = " + uc);
        System.out.println("LowerCase Count = " + lc);
        System.out.println("Digit count = " + dc);
        System.out.println("Special Character Count = " + sc);
        
    }
}

Write a program to enter a sentence from the keyboard and count the number of times a particular word occurs in it. Display the frequency of the search word.

Sample Input:
Enter a sentence: The quick brown fox jumps over the lazy dog.
Enter a word to search: the

Sample Output:
Search word occurs 2 times

import java.util.Scanner;

public class KboatWordFrequency
{
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter a sentence: ");
        String str = in.nextLine();
        System.out.print("Enter a word to search: ");
        String ipWord = in.nextLine();
        str += " ";
        String word = "";
        int count = 0;
        int len = str.length();

        for (int i = 0; i < len; i++) {
            if (str.charAt(i) == ' ') {

                if (word.equalsIgnoreCase(ipWord))
                    count++ ;

                word = "";
            }
            else {
                word += str.charAt(i);
            }
        }
        
        if (count > 0) {
            System.out.println("Search word occurs " + count + " times.");
        }
        else {
            System.out.println("Search word is not present in sentence.");
        }
        
    }
}

Write a program in Java to enter a string/sentence and display the longest word and the length of the longest word present in the string.

Sample Input:
"Tata football academy will play against Mohan Bagan"

Sample Output:
The longest word: Football
The length of the word: 8

import java.util.Scanner;

public class KboatLongestWord
{
    public static void main(String args[]) {
       Scanner in = new Scanner(System.in);
       System.out.println("Enter a word or sentence:");
       String str = in.nextLine();
       
       str += " "; //Add space at end of string
       String word = "", lWord = "";
       int len = str.length();
       
       for (int i = 0; i < len; i++) {
           char ch = str.charAt(i);
           if (ch == ' ') {
               
                if (word.length() > lWord.length())
                    lWord = word;
                    
                word = "";
           }
           else {
               word += ch;
           }
       }
       
       System.out.println("The longest word: " + lWord +
        ": The length of the word: " + lWord.length());
    }
    
}

Write a program to accept a string. Convert the string to uppercase. Count and output the number of double letter sequences that exist in the string.

Sample Input:
"SHE WAS FEEDING THE LITTLE RABBIT WITH AN APPLE"

Sample Output:
4

import java.util.Scanner;

public class KboatLetterSeq
{
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter string: ");
        String s = in.nextLine();
        String str = s.toUpperCase();
        int count = 0;
        int len = str.length();
        
        for (int i = 0; i < len - 1; i++) {
            if (str.charAt(i) == str.charAt(i + 1))
                count++;
        }
        
        System.out.println("Double Letter Sequence Count = " + count);
        
    }
}

Write a program to input twenty names in an array. Arrange these names in descending order of alphabets, using the bubble sort technique.

import java.util.Scanner;

public class KboatArrangeNames
{
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        String names[] = new String[20];
        System.out.println("Enter 20 names:");
        for (int i = 0;  i < names.length; i++) {
            names[i] = in.nextLine();
        }

        //Bubble Sort
        for (int i = 0; i < names.length - 1; i++) {
            for (int j = 0; j < names.length - 1 - i; j++) {
                if (names[j].compareToIgnoreCase(names[j + 1]) < 0) {
                    String temp = names[j + 1];
                    names[j + 1] = names[j];
                    names[j] = temp;
                }
            }
        }
        
        System.out.println("\nSorted Names");
        for (int i = 0;  i < names.length; i++) {
            System.out.println(names[i]);
        }
    }
}

Given below is a hypothetical table showing rates of Income Tax for male citizens below the age of 65 years:

Write a program to input the age, gender (male or female) and Taxable Income of a person. If the age is more than 65 years or the gender is female, display "wrong category".

If the age is less than or equal to 65 years and the gender is male, compute and display the Income Tax payable as per the table given above.

import java.util.Scanner;

public class KboatIncomeTax
{
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter Gender(male/female): ");
        String gender = in.nextLine();
        System.out.print("Enter Age: ");
        int age = in.nextInt();
        System.out.print("Enter Taxable Income: ");
        double ti = in.nextDouble();
        double tax = 0.0;

        if (age > 65 || gender.equalsIgnoreCase("female")) {
            System.out.print("Wrong Category");
        }
        else {
            if (ti <= 160000)
                tax = 0;
            else if (ti <= 500000)
                tax = (ti - 160000) * 10 / 100;
            else if (ti <= 800000)
                tax = 34000 + ((ti - 500000) * 20 / 100);
            else
                tax = 94000 + ((ti - 800000) * 30 / 100);
                
            System.out.println("Tax Payable: " + tax);
        }      
    }
}

Write a program to accept the names of 10 cities in a single dimensional string array and their STD (Subscribers Trunk Dialling) codes in another single dimensional integer array. Search for a name of a city input by the user in the list. If found, display "Search Successful" and print the name of the city along with its STD code, or else display the message "Search Unsuccessful, No such city in the list".

import java.util.Scanner;

public class KboatStdCodes
{
    public static void main(String args[]) {
        final int SIZE = 10;
        Scanner in = new Scanner(System.in);
        String cities[] = new String[SIZE];
        String stdCodes[] = new String[SIZE];
        System.out.println("Enter " + SIZE + 
                 " cities and their STD codes:");
        
        for (int i = 0;  i < SIZE; i++) {
            System.out.print("Enter City Name: ");
            cities[i] = in.nextLine();
            System.out.print("Enter its STD Code: ");
            stdCodes[i] = in.nextLine();
        }
        
        System.out.print("Enter name of city to search: ");
        String city = in.nextLine();
        
        int idx;
        for (idx = 0;  idx < SIZE; idx++) {
            if (city.compareToIgnoreCase(cities[idx]) == 0) {
                break;
            }
        }
        
        if (idx < SIZE) {
            System.out.println("Search Successful");
            System.out.println("City: " + cities[idx]);
            System.out.println("STD Code: " + stdCodes[idx]);
        }
        else {
            System.out.println("Search Unsuccessful");
        }
    }
}

Write a program to input forty words in an array. Arrange these words in descending order of alphabets, using selection sort technique. Print the sorted array.

import java.util.Scanner;

public class KboatSelectionSort
{
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        String a[] = new String[40];
        int n = a.length;
        
        System.out.println("Enter 40 Names: ");
        for (int i = 0; i < n; i++) {
            a[i] = in.nextLine();
        }
        
        for (int i = 0; i < n - 1; i++) {
            int idx = i;
            for (int j = i + 1; j < n; j++) {
                if (a[j].compareToIgnoreCase(a[idx]) < 0) {
                    idx = j;
                }
            }
            String t = a[idx];
            a[idx] = a[i];
            a[i] = t;
        }
        
        System.out.println("Sorted Names");
        for (int i = 0; i < n; i++) {
            System.out.println(a[i]);
        }
    }
}

Define a class named movieMagic with the following description:

Instance Variables/Data Members:
int year - to store the year of release of a movie
String title - to store the title of the movie.
float rating - to store the popularity rating of the movie.
(minimum rating = 0.0 and maximum rating = 5.0)

Member Methods:
i. movieMagic() - Default constructor to initialise numeric data members to 0 and String data member to "".
ii. void accept() - To input and store year, title and rating.
iii. void display() - To display the title of a movie and a message based on the rating as per the table given below.

Write a main method to create an object of the class and call the above member methods.

import java.util.Scanner;

public class movieMagic
{
    private int year;
    private String title;
    private float rating;
    
    public movieMagic() {
        year = 0;
        title = "";
        rating = 0.0f;
    }
    
    public void accept() {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter Title of Movie: ");
        title = in.nextLine();
        System.out.print("Enter Year of Movie: ");
        year = in.nextInt();
        System.out.print("Enter Rating of Movie: ");
        rating = in.nextFloat();
    }
    
    public void display() {
        String message = "Invalid Rating";
        if (rating <= 2.0f)
            message = "Flop";
        else if (rating <= 3.4f)
            message = "Semi-Hit";
        else if (rating <= 4.4f)
            message = "Hit";
        else if (rating <= 5.0f)
            message = "Super-Hit";
            
        System.out.println(title);
        System.out.println(message);
    }
    
    public static void main(String args[]) {
        movieMagic obj = new movieMagic();
        obj.accept();
        obj.display();
    }
}

Write a program to accept name and total marks of N number of students in two single subscripts array name[] and totalmarks[].

Calculate and print:
i. The average of the total marks obtained by N number of students. [average = (sum of total marks of all the students) / N]

ii. Deviation of each student's total marks with the average. [deviation = total marks of a student - average]

import java.util.Scanner;

public class KboatSDAMarks
{
    public static void main(String args[]) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter number of students: ");
        int n = in.nextInt();
        
        String name[] = new String[n];
        int totalmarks[] = new int[n];
        int grandTotal = 0;
        
        for (int i = 0; i < n; i++) {
            in.nextLine();
            System.out.print("Enter name of student " + (i+1) + ": ");
            name[i] = in.nextLine();
            System.out.print("Enter total marks of student " + (i+1) + ": ");
            totalmarks[i] = in.nextInt();
            grandTotal += totalmarks[i];
        }
        
        double avg = grandTotal / (double)n;
        System.out.println("Average = " + avg);
        
        for (int i = 0; i < n; i++) {
            System.out.println("Deviation for " + name[i] + " = " 
            + (totalmarks[i] - avg));
        }
    }
}

Design a class RailwayTicket with the following description:

Instance Variables/Data Members:

String name: to store the name of the customer.
String coach: to store the type of coach customer wants to travel in.
long mobno: to store customer's mobile number.
int amt: to store basic amount of ticket.
int totalamt: to store the amount to be paid after updating the original amount.

Methods:

void accept(): to take input for name, coach, mobile number and amount.
void update(): to update the amount as per the coach selected.

Extra amount to be added in the amount as follows:

void display(): To display all details of a customer such as name, coach, total amount and mobile number.

Write a main() method to create an object of the class and call the above methods.

import java.util.Scanner;

public class RailwayTicket
{
    private String name;
    private String coach;
    private long mobno;
    private int amt;
    private int totalamt;
    
    private void accept() {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter name: ");
        name = in.nextLine();
        System.out.print("Enter coach: ");
        coach = in.nextLine();
        System.out.print("Enter mobile no: ");
        mobno = in.nextLong();
        System.out.print("Enter amount: ");
        amt = in.nextInt();
    }
    
    private void update() {
        if(coach.equalsIgnoreCase("First_AC"))
            totalamt = amt + 700;
        else if(coach.equalsIgnoreCase("Second_AC"))
            totalamt = amt + 500;
        else if(coach.equalsIgnoreCase("Third_AC"))
            totalamt = amt + 250;
        else if(coach.equalsIgnoreCase("Sleeper"))
            totalamt = amt;
    }
    
    private void display() {
        System.out.println("Name: " + name);
        System.out.println("Coach: " + coach);
        System.out.println("Total Amount: " + totalamt);
        System.out.println("Mobile number: " + mobno);
    }
    
    public static void main(String args[]) {
        RailwayTicket obj = new RailwayTicket();
        obj.accept();
        obj.update();
        obj.display();
    }
}

Design a class to overload a function check() as follows:

public class KboatOverload
{
    void check (String str , char ch ) {
        int count = 0;
        int len = str.length();
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            if (ch == c) {
                count++;
            }
        }
        System.out.println("Frequency of " + ch + " = " + count);
    }
    
    void check(String s1) {
        String s2 = s1.toLowerCase();
        int len = s2.length();
        System.out.println("Vowels:");
        for (int i = 0; i < len; i++) {
            char ch = s2.charAt(i);
            if (ch == 'a' ||
                ch == 'e' ||
                ch == 'i' ||
                ch == 'o' ||
                ch == 'u')
                System.out.print(ch + " ");
        }
    }
}

Design a class to overload a function Joystring() as follows:

1. void Joystring(String s, char ch1, char ch2) with one string argument and two character arguments that replaces the character argument ch1 with the character argument ch2 in the given string s and prints the new string.
   Example:
   Input value of s = "TECHNALAGY"
   ch1 = 'A',
   ch2='O'
   Output: "TECHNOLOGY"
2. void Joystring(String s) with one string argument that prints the position of the first space and the last space in the given string s.
   Example:
   Input value of s = "Cloud computing means Internet based computing"
   Output:
   First index : 5
   Last index : 36
3. void Joystring (String s1, String s2) with two string arguments that combines the two strings with a space between them and prints the resultant string.
   Example:
   Input value of s1 ="COMMON WEALTH"
   Input value of s2 = "GAMES"
   Output: COMMON WEALTH GAMES

(use library functions)

public class KboatStringOverload
{
    public void joystring(String s, char ch1, char ch2) {
        String newStr = s.replace(ch1, ch2);
        System.out.println(newStr);
    }
    
    public void joystring(String s) {
        int f = s.indexOf(' ');
        int l = s.lastIndexOf(' ');
        System.out.println("First index:  " + f);
        System.out.println("Last index:  " + l);
    }
    
    public void joystring(String s1, String s2) {
        String newStr = s1.concat(" ").concat(s2);
        System.out.println(newStr);
    }
    
    public static void main(String args[]) {
        KboatStringOverload obj = new KboatStringOverload();
        obj.joystring("TECHNALAGY", 'A', 'O');
        obj.joystring("Cloud computing means Internet based computing");
        obj.joystring("COMMON WEALTH", "GAMES");
    }
}

Design a class to overload a function num_calc() as follows:

import java.util.Scanner;

public class KboatChoiceOverload
{
    void num_calc(int mini, char ch) {
        if (ch == 's') {
            long sq = mini * mini;
            System.out.println("Square = " + sq );
        }
        else {
            long cube = mini * mini * mini;
            System.out.println("Cube = " + cube);
        }
    }
    
    void num_calc(int a, int b, char ch) {
        if (ch == 'p') {
            long prod = a * b;
            System.out.println("Product = " + prod );
        }
        else {
            long sum = a + b;
            System.out.println("Sum = " + sum);
        }
    }
    
    void num_calc(String s1, String s2)    {
        if(s1.equals(s2))   
            System.out.println("Strings are equal");
        else
            System.out.println("Strings are not equal");
    }
    
}

Design a class to overload a function compare( ) as follows:

import java.util.Scanner;

public class KboatCompare
{
    public void compare(int a, int b) {
        
        if (a > b) {
            System.out.println(a);
        }
        else {
            System.out.println(b);
        }
        
    }
    
    public void compare(char a, char b) {
        int x = (int)a;
        int y = (int)b;
        
        if (x > y) {
            System.out.println(a);
        }
        else {
            System.out.println(b);
        }
        
    }
    
    public void compare(String a, String b) {
        
        int l1 = a.length();
        int l2 = b.length();
        
        if (l1 > l2) {
            System.out.println(a);
        }
        else {
            System.out.println(b);
        }

    }
    
}