# Some Java programs part-5

21. Write a program that will calculate the value of Z if the expression of y is as follows (n is the input):

/* Time: 12:28am * Author : Anik Das*/ import java.util.Scanner; public class Faraz21{ public static void main ( String [] args ){ int a = 1, c=1, n = 0; double z = 0; double sum1=0.0, sum2=0.0; Scanner input = new Scanner ( System.in ); System.out.println("Enter Value OF n"); n = input.nextInt(); while (c<=n){ if (c%2!=0){ sum1 = sum1 + Math.pow(c,2); }else{ sum2 = sum2 - Math.pow(c,2); } c++; } int sum = (int) (sum1+sum2); z = Math.pow(sum,3); System.out.println("Value Of Z is"+z); } }

22. Write a program that will calculate the value of y if the expression of y is as follows (n is the input):

/*Time : 7.37am * Author: Anik Das*/ import java.util.Scanner; public class Faraz22{ public static void main ( String [] args ){ double n = 0, c = 1, sum = 0; Scanner input = new Scanner ( System.in ); System.out.println("Enter The Value Of N :"); n = input.nextDouble(); while (c<=n){ sum = sum + (c/(2*c - 1)); c++; } System.out.println("The Value Of Y is : "+sum); } }

23. Write a program, which adds all the multiples of 7 and 9 up to 300. 24. . An integer number is said to be a perfect number if its factors, including 1 but not the number itself, sum to the number. For example, 6 is a perfect number because 6 = 1 + 2 + 3. Write a complete flowchart of a program, which finds and prints all perfect numbers that are less than 1600.

/* Time: 10:30 am * Author : Anik Das*/ public class Faraz23{ public static void main ( String [] args ){ int sum=0, c = 1 ; while ( c<=300 ){ if ((c%7==0)||(c%9==0)){ sum = sum + c; } c++; } System.out.println("Sum Is : "+sum); } }

25. Write a program that finds and displays all the prime numbers less than 1000.

/* Time : 10:53 am * Author : Anik Das */ public class Faraz25{ public static void main ( String [] args ){ int c = 1, sum = 0; while (c<=11){ int n=1, k=0; while (n<=c){ if(c%n==0){ k=k+1; } n++; } if (k==2){ sum = sum + c; System.out.println("Perfect Number : "+c); } c++; } System.out.println("Sum : "+sum); } }

A. N. M. Bazlur Rahman

April 4, 2011@ 10:57 pmnice ! Liked! Keep it up.

Thanks

anik

April 6, 2011@ 2:00 pmWelcome vaia for your inspirational words… 🙂