Programming In Java | Week 8

Programming In Java Week 8 Answers NPTEL

Quiz

Q1. Which of the following is NOT a class of java.awt package?
a. Color
b. Composite
c. Container
d. Cursor

Q2. Which of the following is/are NOT an exception of java.awt package?
a. HeadlessException
b. AWTException
c. FontFormatException
d. IllegalStateException

Q3. Which of the following method is/are of class button in java.awt package?
a. getLabel()
b. setLabel(String label)

c. getCurrent()
d. getltem(int index)

Q4. Which of the following is TRUE about the following GUI?

a. There is a Frame and two TextFields.
b. There is a Frame with two Labels and two non-editable TextFields.
c. There are two Labels.
d. There is a Frame with two Labels and two TextFields.

Q5. Which of the following is TRUE regarding check box and radio button?
a. Check box is used for single selection item whereas radio button is used for multiple selection.
b. Check box is used for multiple selection items whereas radio button is used for single selection.
c. Both are used for multiple as well as single item selection.
d. Checkbox is always preferred than radio buttons.

Q6. Which of the following is TRUE about check box in Java?
a. A check box can be in either an “on” (true) or “off” (false) state.

b. Clicking on a check box changes its state from “on” to “off.” or from “off” to “on.”
c. A check box can be in an “on” (true) and in “off” (false) state simultaneously.
d. Check boxes cannot be grouped together.

Q7. Which of the following method is used to remove all items from scrolling list in java.awt.list?
a. hide()
b. remove()
c. clear()
d. close()

Q8. Which of the following statement is FALSE about the update() in java.awt package?
a. Sets the color of the graphics context to be the foreground color of this component.
b. Calls this component’s paint method to completely redraw this component.
c. Updates the component by checking an online repository.
d. Clears this component by filling it with the background color.

Q9. Which of the following is the latest graphics and media package for Java?
a. Applet
b. AWT
c. Swing
d. JavaFX

Q10. If setText(String text) is a method of Label class, then why it is called non editable?
a. Because user-input is unavailable during runtime.
b. A Label is just a TextField with non-editable property turned on.
c. Labels are editable by default.
d. setText(String text) is not a method of Label class.

Assignment

1. Write a program which will print a pyramid of “*” ‘s of height “n” and print the number of “*” ‘s in the pyramid.
For example:
Input : 5
Output:  
        * 
      * * * 
    * * * * * 
  * * * * * * * 
* * * * * * * * * 
25

Solution:

import java.util.*;
public class Pattern1 {
    public static void main(String[] args) {
        Scanner inr = new Scanner(System.in);
	   int n = inr.nextInt();
        int k = 0,sum=0;
        for(int i = 1; i <= n; ++i, k = 0) {
            for(int space = 1; space <= n - i; ++space) {
                System.out.print("  ");
            }
            while(k != 2 * i - 1) {
                System.out.print("* ");
                sum=sum+1;
                ++k;
            }
            System.out.println();
        }
         System.out.println(sum); 
    }
}

2. Write a program which will print a pascal  pyramid of  “*” ‘s of height “l” .
For example:
input: 8
output :
       * 
      * * 
     * * * 
    * * * * 
   * * * * * 
  * * * * * * 
 * * * * * * * 
* * * * * * * * 

Solution:

import java.util.*;
public class Pattern2 {
    public static void main(String[] args) {
        Scanner inr = new Scanner(System.in);
	   int l = inr.nextInt();
        int i,j;
        int space=l-1;
     for(i=0;i< l;i++)
       {
	    for(j=0;j< space;j++)
	    {
		    System.out.print(" ");
	    }
	    for(j=0;j<=i;j++)
	    {
		    System.out.print("* ");
	    }
		
	    System.out.print("\n");
	    space--;
         }
   	}
}

3. Write a program which will print a pyramid of “numbers” ‘s of height “n” and print the sum of all number’s in the pyramid.
For example:
input: 5
output: 
        1 
      1 2 3 
    1 2 3 4 5 
  1 2 3 4 5 6 7 
1 2 3 4 5 6 7 8 9 
95

Solution:

import java.util.*;
public class Pattern3 {
    public static void main(String[] args) {
        Scanner inr = new Scanner(System.in);
	   int n = inr.nextInt();
        int k = 1,sum=0;
        for(int i = 1; i <= n; ++i, k = 1) {
            for(int space = 1; space <= n-i; ++space) {
                System.out.print("  ");
            }
            while(k <= 2 * i - 1) {
                System.out.print(k+" ");
                sum=sum+k;
                ++k;
            }
            System.out.println();
        }
         System.out.println(sum); 
    }
}

4. Write a program to print symmetric Pascal’s triangle of “*” ‘s of  height “l” of odd length . If input “l” is even then your program will print “Invalid line number”.
For example:
input : 5
output:
*
 * *
* * *
 * *
  *
input : 6
output:
Invalid line number

Solution:

import java.util.*;
public class Pattern4 {
    public static void main(String[] args) {
        Scanner inr = new Scanner(System.in);
	   int l = inr.nextInt();
         int ul=0; // Upper Line
	   int ll=0; // Lower Line
	  	
	// Check whether line number is odd
	   if (l%2!=0){
	   ul=(l/2)+1;			
	   ll=l-ul;
	//Code for upper half
	for(int i=1;i<=ul; i++){	
	//Space management
	for(int s=1;s<=(ul-i); s++){
	    System.out.print(" ");
	}
	// Star management
	for(int j=1;j<=i; j++){
	     System.out.print("* ");
	}
	System.out.println();
	}
			
	//Code for lower half
	int llc=ll;
	for(int i=1;i<=ll; i++){
	//Space management
	for(int s=llc;s<ll; s++){
	   System.out.print(" ");
	}
	// Star management
	for(int j=1;j-1<=ll-i; j++){
	   System.out.print(" *");
	 }
	 llc--;
	System.out.println();
        }
	}
        else{
	   System.out.print("Invalid line number");
	}

    }
}

5. Write a program to display any digit(n) from 0-9 represented as a “7 segment  display”. 
For example:
input : 5
output :
 _ 
|_ 
 _|
input : 4
output :
|_|
  |

Solution:

import java.util.*;
public class Pattern5 {
    private static final Map<Integer, Integer> encodings =
        new HashMap<Integer, Integer>();
    static {
        encodings.put(0, 0x7E);
        encodings.put(1, 0x30);
        encodings.put(2, 0x6D);
        encodings.put(3, 0x79);
        encodings.put(4, 0x33);
        encodings.put(5, 0x5B);
        encodings.put(6, 0x5F);
        encodings.put(7, 0x70);
        encodings.put(8, 0x7F);
        encodings.put(9, 0x7B);
    }
    public static void printDigit(int digit) {
        int code = encode(digit);
        char[] bits =
            String.format("%7s", Integer.toBinaryString(code))
                .replace(' ', '0').toCharArray();

        lightSegment(bits[0] == '1', " _ \n", "   \n");
        lightSegment(bits[5] == '1', "|", " ");
        lightSegment(bits[6] == '1', "_", " ");
        lightSegment(bits[1] == '1', "|\n", " \n");
        lightSegment(bits[4] == '1', "|", " ");
        lightSegment(bits[3] == '1', "_", " ");
        lightSegment(bits[2] == '1', "|\n", " \n");
    }

    private static void lightSegment(boolean on, String onValue, String offValue) {
        System.out.print(on ? onValue : offValue);
        try {
            Thread.sleep(0);
        }
        catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    private static int encode(int digit) {
       return encodings.containsKey(digit) ? encodings.get(digit) : 0x00;
    }
   public static void main(String[] args) throws Exception {
           Scanner inr = new Scanner(System.in);
	      int n = inr.nextInt();
           printDigit(n);       
    }
}

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