Question

Please show screenshot outputs and fully functional code for the Java programs.

Question 1:

Write a method that computes and returns the area of a square using the following header:

public static double area ( double side)

Write a main method that prompts the user to enter the side of a square, calls the area method then displays the area.

Question 1a:

Write a method that converts miles to kilometers using the following header:

public static double convertToKilometers (double miles)

Write a main method that prompts the user to enter the value of miles, calls the method then displays the value of kilometers.

Question 1b:

Write a method that will replace the spaces in a sentence with dashes (-).

public static String replaceWithDash(String aSentence)

Write a main method that prompts the user to enter a sentence, calls the method then displays the new sentence

Question 1c:

Write 2 methods: one to find the maximum of three integer numbers and the other to find the minimum of three integer numbers

public static int findMax(int n1, int n2, int n3)

public static int findMin(int n1, int n2, int n3)

Write a main method that prompts the user to enter the three values, calls the methods then displays the value of maximum number then the value of the minimum number.

Question 1d:

Write a method to generate a random vehicle plate number.

public static String generatePlateNum()

Write a main method that will call the method and then print the vehicle plate number

Question 1e:

Write a method to calculate the sum of 10 integer numbers. The method will ask the user to enter the 10 numbers and calculate the sum.

public static int calcSum()

Write a test program (main method) that will call the method and then print the sum.

Answer 1

Q1.

import java.util.*;
import java.lang.*;
import java.io.*;
class Q1
{
   public static double area(double side)
   {
       double area;
       area=side*side;
       return area;
   }
   public static void main (String[] args) throws java.lang.Exception
   {
       BufferedReader x=new BufferedReader(new InputStreamReader(System.in));
       System.out.println("enter the side of the square:");
       double side=Double.parseDouble(x.readLine());
       System.out.println("area of the square is:"+area(side));
   }
}

Q1a.

import java.util.*;
import java.lang.*;
import java.io.*;
class Q2
{
   public static double convertToKilometers(double miles)
   {
       double km;
       km=1.60934*miles;
       return km;
   }
   public static void main (String[] args) throws java.lang.Exception
   {
       BufferedReader x=new BufferedReader(new InputStreamReader(System.in));
       System.out.println("enter the value of miles:");
       double miles=Double.parseDouble(x.readLine());
       System.out.println("value of kilometers:"+convertToKilometers(miles));
   }
}

Q1b.

import java.util.*;
import java.lang.*;
import java.io.*;
class Q3
{
   public static String replaceWithDash(String aSentence)
   {
       String s=" ";
       int i;
       for(i=0;i<aSentence.length();i++)
       {
           if(aSentence.charAt(i)==' ') //checking if the char at ith index is a blank space
           s=s+"-"; //here we are adding - instead of blank spaces in the new string
           else //if not blank space we add the characet to the new string
           s=s+aSentence.charAt(i); //here we are adding the character present at ith index
       }
       return s;
   }
   public static void main (String[] args) throws java.lang.Exception
   {
       Scanner x=new Scanner(System.in);
       System.out.println("enter a sentence:");
       String aSentence=x.nextLine();
       System.out.println("the new sentence:"+replaceWithDash(aSentence));
   }
}

Q1c.

import java.util.*;
import java.lang.*;
import java.io.*;
class Q4
{
   public static int findMax(int n1, int n2, int n3)
   {
       return (n1>n2)?((n1>n3)?n1:n3):((n2>n3)?n2:n3); //using nested ternary operator to find max
   }
   public static int findMin(int n1, int n2, int n3)
   {
       return (n1<n2)?((n1<n3)?n1:n3):((n2<n3)?n2:n3); //using nested ternary operator to find min
   }
   public static void main (String[] args) throws java.lang.Exception
   {
       BufferedReader x=new BufferedReader(new InputStreamReader(System.in));
       System.out.println("enter the 1st integer:");
       int n1=Integer.parseInt(x.readLine());
       System.out.println("enter the 2nd integer:");
       int n2=Integer.parseInt(x.readLine());
       System.out.println("enter the 3rd integer:");
       int n3=Integer.parseInt(x.readLine());
       System.out.println("value of maximum number:"+findMax(n1,n2,n3));
       System.out.println("value of minimum number:"+findMin(n1,n2,n3));
   }
}

Q1d.

import java.util.*;
import java.lang.*;
import java.io.*;
class Q5
{
   public static String generatePlateNum()
   {
       StringBuilder platenum = new StringBuilder();
       for (int i = 0; i < 3; i++)
       {
           char alpha= (char)(Math.random()* 26 + 'A');
           platenum.append(alpha);
          
       }
       for (int i = 0; i < 4; i++)
       {
           char num=(char)(Math.random()*10+'0');
           platenum.append(num);
       }
       String s=" ";
           for (int i = 0; i < 7; i++)
           {
               s=s+platenum.charAt(i);
           }
           return s;
   }
public static void main (String[] args) throws java.lang.Exception
   {
       System.out.println("the random vehicle plate number is:"+generatePlateNum());
   }
}

Q1e.

import java.util.*;
import java.lang.*;
import java.io.*;
class Q6
{
   static int arr[]=new int[10];
   Q6()
   {
       int i;
       for(i=0;i<10;i++)
       {
           arr[i]=0;
       }
   }
   public static int calcSum()
   {
       int sum=0,i;
       for(i=0;i<10;i++)
       {
           sum=sum+arr[i];
       }
       return sum;
   }
   public static void main (String[] args) throws java.lang.Exception
   {
       int i;
       Q6 a=new Q6(); //creating object of the class Q6
       BufferedReader x=new BufferedReader(new InputStreamReader(System.in));
       System.out.println("enter the array:");
       for(i=0;i<10;i++)
       {
       System.out.println("enter the an integer:");
       a.arr[i]=Integer.parseInt(x.readLine());
       }
       System.out.println("the sumof the 10 integer numbers is:"+a.calcSum());
   }
}