1. Write a Java program that asks the user to enter a distance in meters. The pr

Question

1. Write a Java program that asks the user to enter a distance in meters. The program will then present the following menu of selections:

Convert to kilometers

Convert to inches

Convert to feet

Quit the program

The program will convert the distance to kilometers (=meters*0.001), inches (=meters*39.37) or feet (=meters*3.281), depending on the user’s selection. Each conversion should be handled by a separate method that takes the distance in meters as an argument.

2. A prime number is a number that is only evenly divisible by itself and 1. For example, the number 5 is prime because it can only be evenly divided (that is with a remainder of zero) by 1 and 5. The number 6 is not prime because it can be evenly divided by 1, 2, 3, and 6. Write a Java program that ask the user for an integer number a writes to a file the prime numbers between 1 and the number entered by the user. The program should include a method named isPrime that takes an integer number as an argument and returns true if the argument is prime, and false if the argument is not prime.

Explanation / Answer

Question 1:

DistanceTest.java

import java.util.Scanner;

public class DistanceTest {

   public static void main(String[] args) {
       Scanner scan = new Scanner(System.in);
       System.out.print("Enter a distance in meters: ");
       double meters = scan.nextDouble();
       while(true){
       System.out.println("Choose your chice: 1.Convert to kilometers 2.Convert to inches 3.Convert to feet 4.Quit Enter your choice:");
       int choice = scan.nextInt();
       switch(choice){
       case 1: convertKilometer(meters); break;
       case 2: convertInches(meters); break;
       case 3: convertFeet(meters); break;
       case 4: System.exit(0);
       }
       }

   }
   public static void convertKilometer(double meters){
       double kilometers =meters*0.001;
       System.out.println("Distance in kilometer: "+kilometers);
   }
public static void convertInches(double meters){
   double inches =meters*39.37;
   System.out.println("Distance in inches : "+inches );
      
   }public static void convertFeet(double meters){
       double feet =meters*3.281;
       System.out.println("Distance in feet: "+feet);
   }
}

Output:

Enter a distance in meters: 10

Choose your chice:
1.Convert to kilometers
2.Convert to inches
3.Convert to feet
4.Quit
Enter your choice:
1
Distance in kilometer: 0.01
Choose your chice:
1.Convert to kilometers
2.Convert to inches
3.Convert to feet
4.Quit
Enter your choice:
2
Distance in inches : 393.7
Choose your chice:
1.Convert to kilometers
2.Convert to inches
3.Convert to feet
4.Quit
Enter your choice:
3
Distance in feet: 32.81
Choose your chice:
1.Convert to kilometers
2.Convert to inches
3.Convert to feet
4.Quit
Enter your choice:
4

Question 2:

Primes.java

import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;

public class Primes {

   public static void main(String[] args) throws FileNotFoundException {
       Scanner scan = new Scanner(System.in);
       System.out.print("Enter an integer number: ");
       int n = scan.nextInt();
       PrintWriter pw = new PrintWriter("primes.txt");
      
       for(int i=1; i<=n; i++){
           if(isPrime(i)){
           System.out.print(i+" ");
           pw.write(i+" ");

}
       }
       System.out.println();
       pw.flush();
       pw.close();
       System.out.println("File has been generated");
   }
   public static boolean isPrime(int n){
       for (int f = 2; f < n / 2; f++) {
   if (n % f == 0) {
   return false;
   }
  
   }
   return true;
   }

}

Output:

Enter an integer number: 100
1 2 3 4 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
File has been generated

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