Q: Question 10What will be the output of the following code snippet when combined with suitable declarations and run?StringBuffer city = new StringBuffer("Madras"); StringBuffer string = new StringBuffer( ); string.append(new String(city)); string.insert(0, "Central "); String.out.println(string);

The given snippet will generate an error in the statement — String.out.println(string); as the correct statement for printing is — System.out.println(string);. After this correction is done, the output will be as follows:OutputCentral Madras ExplanationStatementRemarkStringBuffer city = new StringBuffer("Madras");It creates a StringBuffer objectcity which stores "Madras".StringBuffer string = new StringBuffer( );It creates an empty StringBuffer object string.string.append(new String(city));It adds the value of city i.e. "Madras" at the end of the StringBuffer object string. string = " Madras".string.insert(0, "Central ");It modifies StringBuffer object string and adds "Central" at 0 index or beginning. Now, string = "Central Madras".System.out.println(string);It prints "Central Madras".

Q: Question 11What will be the output for the following program segment?String s = new String ("abc"); System.out.println(s.toUpperCase( ));

OutputABC ExplanationString s stores "abc".toUpperCase( ) method converts all of the characters in the String to upper case. Thus, "abc" is converted to "ABC" and printed on the output screen.

Question 1

Question 1How do you create strings implicitly and explicitly?

Accepted Answer

To create a string implicitly, we write a series of characters enclosed in double quotes. After doing so, the Java compiler implicitly creates an object of the String class and assigns it the value written in double quotes.For example,String day = "MONDAY";To create a string explicitly, we use the keyword — new. There is a constructor in the String class that accepts a string as a parameter and creates a unique string.For example,String day = new String("MONDAY");

Question 2

Question 2How are Strings different from StringBuffers ?

Accepted Answer

The string objects of Java are immutable i.e., once created, they cannot be changed. If any change occurs in a string object, then original string remains unchanged and a new string is created with the changed string.On the other hand, StringBuffer objects are mutable. Thus, these objects can be manipulated and modified as desired.

Question 3

Question 3How can you convert a numeric value enclosed in a string format ?

Accepted Answer

We can convert a numeric value enclosed in a string format into a numeric value by using valueOf() method.For example, the given statement will return the numeric value of the String argument "15".int num = Integer.valueOf("15");

Question 4

Question 5State the data type and values of a and b after the following segment is executed.String s1 = "Computer", s2 = "Applications"; 
a = (s1.compareTo(s2));
b = (s1.equals(s2));

Accepted Answer

Data type of a is int and value is 2. Data type of b is boolean and value is false.ExplanationcompareTo() method compares two strings lexicographically and returns the difference between the ASCII values of the first differing characters in the strings. Thus, a will be of int data type and store the value 2 as the difference between ASCII values of 'A' and 'C' is 2.equals() method compares two String objects and returns true if the strings are same, else it returns false. Thus, b will be of boolean data type and result in false as both the strings are not equal.

Question 5

Question 6What do the following functions return for :String x = "hello"; 
String y = "world";(i) System.out.println(x + y);(ii) System.out.println(x.length( ));(iii) System.out.println(x.charAt(3));(iv) System.out.println(x.equals(y));

Accepted Answer

(i) System.out.println(x + y);Outputhelloworld
Explanation+ operator concatenates String objects x and y.(ii) System.out.println(x.length( ));Output5
Explanationlength() returns the length of the String object. Since x has 5 characters, the length of the string is 5.(iii) System.out.println(x.charAt(3));Outputl
ExplanationchatAt() returns the character at the given index. Index starts from 0 and continues till length - 1. Thus, the character at index 3 is l.(iv) System.out.println(x.equals(y));Outputfalse
Explanationequals() method checks for value equality, i.e., whether both objects have the same value regardless of their memory location. As values of x and y are not the same, so the method returns false.

Question 6

Question 7What will the following code output ?String s = "malayalam" ;
System.out.println(s.indexOf('m')); 
System.out.println(s.lastIndexOf('m'));

Accepted Answer

Output0
8
ExplanationindexOf() returns the index of the first occurrence of the specified character within the current String object. The first occurrence of 'm' is at index 0, thus 0 is printed first.lastIndexOf() returns the index of the last occurrence of the specified character within the String object. The last occurrence of 'm' is at index 8, thus 8 is printed next.

Question 7

Question 8If:String x = "Computer";  
String y = "Applications";What do the following functions return?(i) System.out.println(x.substring(1,5));(ii) System.out.println(x.indexOf(x.charAt(4)));(iii) System.out.println(y + x.substring(5));(iv) System.out.println(x.equals(y));

Accepted Answer

(i) System.out.println(x.substring(1,5));Outputompu
Explanationx.substring(1,5) will return a substring of x starting at index 1 till index 4 (i.e. 5 - 1 = 4).(ii) System.out.println(x.indexOf(x.charAt(4)));Output4
ExplanationcharAt() method returns the character at a given index in a String. Thus, x.charAt(4) will return the character at the 4th index i.e., u. indexOf() method returns the index of the first occurrence of a given character in a string. Thus, it returns the index of u, which is 4.(iii) System.out.println(y + x.substring(5));OutputApplicationster
Explanationx.substring(5) will return the substring of x starting at index 5 till the end of the string. It is "ter". This is added to the end of string y and printed to the console as output.(iv) System.out.println(x.equals(y));Outputfalse
Explanationequals() method checks for value equality, i.e., whether both objects have the same value regardless of their memory location. As the values of both x and y are different so it returns false.

Question 8

Question 2(viii)Mention the purpose and syntax of compareToIgnore() method.

Accepted Answer

The compareToIgnore() method compares two strings lexicographically, ignoring case differences in the strings. It returns a value based on the following logic:if string1 > string2 the result will be a positive integer, i.e., result > 0if string1 < string2 the result will be a negative integer, i.e., result < 0if string1 = string2 the result will be 0, i.e., result = 0Syntax:string1.compareToIgnore(string2)

Question 9

Question 10What will be the output of the following code snippet when combined with suitable declarations and run?StringBuffer city = new StringBuffer("Madras"); 
StringBuffer string = new StringBuffer( ); 
string.append(new String(city)); 
string.insert(0, "Central "); 
String.out.println(string);

Accepted Answer

The given snippet will generate an error in the statement — String.out.println(string); as the correct statement for printing is — System.out.println(string);. After this correction is done, the output will be as follows:OutputCentral Madras
ExplanationStatementRemarkStringBuffer city = new StringBuffer("Madras");It creates a StringBuffer objectcity which stores "Madras".StringBuffer string = new StringBuffer( );It creates an empty StringBuffer object string.string.append(new String(city));It adds the value of city i.e. "Madras" at the end of the StringBuffer object string. string = " Madras".string.insert(0, "Central ");It modifies StringBuffer object string and adds "Central" at 0 index or beginning. Now, string = "Central Madras".System.out.println(string);It prints "Central Madras".

Question 10

Question 11What will be the output for the following program segment?String s = new String ("abc");
System.out.println(s.toUpperCase( ));

Accepted Answer

OutputABC
ExplanationString s stores "abc".toUpperCase( ) method converts all of the characters in the String to upper case. Thus, "abc" is converted to "ABC" and printed on the output screen.

Question 11

Question 12Give the output of the following program :class MainString
{
    public static void main(String[ ] args)
    {
        StringBuffer s = new StringBuffer("String"); 
        if((s.length( ) > 5) && 
        (s.append("Buffer").equals("X")))
        ;	// empty statement
        System.out.println(s);
    }
}

Accepted Answer

OutputStringBuffer
ExplanationThe expression s.length( ) > 5 will result in true because the length of String s is 6 which is > 5.In the expression s.append("Buffer".equals("X")), first the value of String s will be modified from String to StringBuffer and then it will be compared to "X". The result will be false as both the values are not equal.Now, the condition of if statement can be solved as follows:if((s.length( ) > 5) && (s.append("Buffer").equals("X")))
if(true && false)
if(false)
Thus, execution will move to the next statement following the if block — System.out.println(s); which will print StringBuffer on the screen.

Question 12

Question 3(ii)Differentiate between equals() and == .

Accepted Answer

equals()==It is a method.It is a relational operator.It is used to check if the contents of two strings are same or not.It is used to check if two variables refer to the same object in memory.Example:String s1 = new String("hello");String s2 = new String("hello");boolean res = s1.equals(s2);System.out.println(res);The output of this code snippet is true as contents of s1 and s2 are the same.Example:String s1 = new String("hello");String s2 = new String("hello");boolean res = s1 == s2;System.out.println(res);The output of this code snippet is false as s1 and s2 point to different String objects.

Question 13

Question 3(iii)Differentiate between startsWith() and endsWith().

Accepted Answer

startsWith()endsWith()startsWith() tests if the string object starts with the string specified as its argument.endsWith() tests if the string object ends with the string specified as its argument.Example:String str = "ICSE Computer Applications";boolean res = str.startsWith("ICSE");System.out.println(res);The output of this code is true as str begins with "ICSE".Example:String str = "ICSE Computer Applications";boolean res = str.endsWith("tions");System.out.println(res);The output of this code is true as str ends with "tions".

Question 14

Question 3(iv)Differentiate between indexOf() and lastIndexOf().

Accepted Answer

indexOf()lastIndexOf()The indexOf() method returns the index of the first occurrence of the specified character in a string.The lastIndexOf() method returns the index of the last occurrence of the specified character in a string.Example:String str = "How are you?";int index = str.indexOf('o');System.out.println("Index = " + index);The output isIndex = 1Example:String str = "How are you?";int index = str.lastIndexOf('o');System.out.println("Index = " + index);The output isIndex = 9

Question 15

Question 3(v)Differentiate between compareTo() and compareToIgnore().

Accepted Answer

compareTo()compareToIgnore()It compares two strings lexicographically.It compares two strings lexicographically, ignoring the case of the characters in a string.Example:String str1 = "computer";String str2 = "COMPUTER";int res = str1.compareTo(str2);System.out.println(res);The output is 32 as 'c' and 'C' are treated differently.Example:String str1 = "computer";String str2 = "COMPUTER";int res = str1.compareToIgnore(str2);System.out.println(res);The output is 0 as case difference is ignored.

Question 16

Question 17Design a class to overload a function check( ) as follows :(i) void check(String str, char ch) - to find and print the frequency of a character in a string.Example:Input :str = "success" ch= 's'Output :number of s present is = 3(ii) void check (String s1) - to display only vowels from string s1, after converting it to lower case.Example:Input:sl = "computer"Output : o u epublic 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 + " ");
        }
    }
}Output

Accepted Answer

Please refer to the full solution above.

Question 17

Question 5Write 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] + " ");
    }
}Output

Accepted Answer

Please refer to the full solution above.

Question 18

Question 6Write 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] + " ");
        }
    }
}Output

Accepted Answer

Please refer to the full solution above.

Question 19

Question 7Write a program to input a string in uppercase and print the frequency of each character.Sample Input : COMPUTER HARDWARESample OutputCharacter	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	Frequency");
        for (int i = 0; i < freqMap.length; i++) {
            if (freqMap[i] > 0) {
                System.out.println((char)(i + 65) 
                            + "		" + freqMap[i]);
            }
        }
    }
}Output

Accepted Answer

Please refer to the full solution above.

Question 20

Question 8Write 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 RamanSample OutputyM eman si namaRimport 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 = "";
            }
        } 
    }
}Output

Accepted Answer

Please refer to the full solution above.

String Handling

Assignment Questions

Objective Type Questions