Java Week 1 Answers/Solutions

 Java Week 1:Q1 To find the perimeter and area of a circle given a value of radius

import java.util.Scanner;  
public class Exercise1_1 {
       public static void main(String[] args) {
Scanner s = new Scanner(System.in); 
       double radius= s.nextDouble();
       double perimeter;
       double area;
//Calculate the perimeter 

	perimeter = 2 * Math.PI * radius;
//Calculate the area
	area = perimeter * radius;
	
	System.out.println(perimeter);
	System.out.println(area);
	}
}

Java Week 41:Q2 To find the largest among three numbers x, y, and z.

import java.util.Scanner;  
public class Exercise1_2 {
      
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in); 
        	int x = s.nextInt(); 
        	int y = s.nextInt();
		int z = s.nextInt();
		int result = 0;
		//Use if...else ladder to find the largest among 3 numbers and store the largest number in a variable called result.

		if( x > y && x > z)
		{
			result = x;
		}
		else if( y > x && y > z)
		{
			result = y;
		}
		else if( z > y && z > x)
		{
			result = z;
		}
		else
		{
			result = x;
		}

		System.out.print(result);
	}

}

Java Week 1:Q3 Consider First n even numbers starting from zero(0) and calculate sum of all the numbers divisible by 3 from 0 to n. Print the sum.
import java.util.Scanner;
public class Exercise1_3 {
       public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n=sc.nextInt();
		int sum=0,t;
 //Use for or while loop do the operation
		for(int i=0;i<=n;i++)
		{
			t = 2*(i-1);
			if(t%3 == 0)
			{
				sum += t;
			}
		}
		System.out.println(sum);
	}
}
Java Week 1:Q4 To check whether the number is an Armstrong number or not.
import java.util.Scanner;
public class Exercise1_4 {
    public static void main(String[] args) {
	   Scanner sc = new Scanner(System.in);
	   int n=sc.nextInt();
           int result=0;
			//Use while loop check the number is Armstrong or not.
			//store the output(1 or 0) in result variable
		int remainder,temp,count=0,i;
		temp=n;
		while(temp!=0)
		{
			temp/=10;
			count++;
		}
		i=count;
		temp=n;
		while(count>0)
		{
			remainder=temp%10;
			result += Math.pow(remainder, i);
			temp/=10;
			count--;
		}
		if(n==result)
			result=1;
		else
			result=0;

		System.out.print(result);

	}
}




Java Week 1:Q5 To help Ram , find the highest mark and average mark secured by him in "s" number of subjects.

import java.util.Scanner;
public class Exercise1_5{
    public static void main(String[] args) {
	 Scanner input = new Scanner(System.in);
         double mark_avg;
         int result;
         int i;
         int s;
      //define size of array
       s = input.nextInt();
     //The array is defined "arr" and inserted marks into it.
      int[] arr = new int[s];   
      
	 for(i=0;i<arr.length;i++)
	  {
        	arr[i]=input.nextInt();
	  } 
 //Initialize maximum element as first element of the array.  
   //Traverse array elements to get the current max.
   //Store the highest mark in the variable result.
   //Store average mark in mark_avg.
	int temp=0,j;
	
 	for(i=0; i < s; i++)
	{  
                for(j=1; j < (s-i); j++)
		{  
			if(arr[j-1] > arr[j])
			{  
                        	//swap elements  
                        	temp = arr[j-1];  
                                arr[j-1] = arr[j];  
                                arr[j] = temp;  
                        }       
                 }  
         } 
	result=arr[s-1];
	temp=0;
	for(i=0;i<arr.length;i++)
	{
		temp +=arr[i];
	}
	mark_avg=temp/s;
	
	System.out.println(result);
	System.out.print(mark_avg);


	}
}