Iterative Constructs in Java

11. Write a program to input n number of integers and find out:

    i. Number of positive integers

   ii. Number of negative integers

  iii. Sum of positive numbers

   iv. Product of negative numbers

   v. Average of positive numbers

12. Write a program using do-while loop to compute the sum of the first 500 positive odd integers.

13. Write three different programs using for, while, and do-while loops to find the product of series 3, 9, 12,... 30.

14. Write a program to convert kilograms to pounds in the following tabular format (1 kilogram is 2.2 pounds):

15. Write a program that displays all the numbers from 150 to 250 that are divisible by 5 or 6, but not both.

16. Write a program in Java to read a number and display its digits in the reverse order. For example, if the input number is 2468, then the output should be 8642.

Output:
Enter a number: 2468
Original number: 2468
Reverse number: 8642

17. Write a program in Java to read a number, remove all zeros from it, and display the new number. For example,

Sample Input: 45407703
Sample Output: 454773

18. Write a program to read the number n using the Scanner class and print the Tribonacci series: 0, 0, 1, 1, 2, 4, 7, 13, 24, 44, 81 . . . and so on.
Hint: The Tribonacci series is a generalisation of the Fibonacci sequence where each term is the sum of the three preceding terms.

19. Write a program to calculate the value of Pi with the help of the following series:
Pi = (4/1) - (4/3) + (4/5) - (4/7) + (4/9) - (4/11) + (4/13) - (4/15) ...
Hint: Use while loop with 100000 iterations.

20. Write a program to display the following patterns as per the user's choice.

Pattern 1           

I

 C

   S

     E

Pattern 2

      I

    C

  S

E

21. Write a menu-driven program to display the pattern as the per user's choice:

     Pattern 1

     ABCDE

     ABCD

     ABC

     AB

     A

     Pattern 2

     B

     LL

     UUU

     EEEE

22. Write a program to input a number and check and print whether it is a Pronic number or not. (Pronic number is a number which is the product of two consecutive integers.)
Example:   12 = 3 x 4
                 20 = 4 x 5
                 42 = 6 x 7

23. Write a program to accept a number and check and display whether it is a spy number or not. (A number is called a spy number if the sum of its digits equals the product of the digits.)
Example:
Consider the number 1124.
Sum of the digits = 1 + 1 + 2 + 4 = 8.
Product of the digits = 1 * 1 * 2 * 4 = 8.

24. Write a program to accept a number and check and display whether it is a Niven number or not. (Niven number number which is divisible by the sum of its digits).
Example:
Consider the number 126.
Sum of its digits is 1 + 2 + 6 = 9 and 126 is divisible by 9.

25. Using the switch statement, write a menu driven program to:

1. (1). Generate and display the first 10 terms of the Fibonacci series 0, 1, 1, 2, 3, 5.... The first two Fibonacci numbers are 0 and 1, and each subsequent number is the sum of the previous two.


2. (2). Find the sum of the digits of an integer that is input.
   Sample Input: 15390
   Sample Output: Sum of the digits = 18
   For an incorrect choice, an appropriate error message should be displayed.

26. Write a menu driven program to accept a number and check and display whether (i) it is a Prime Number or not (ii) it is an Automorphic Number or not. (Use switch-case statement).

1. (i). Prime number: A number is said to be a prime number if it is divisible only by 1 and itself and not by any other number. Example: 3, 5, 7, 11, 13 etc.


2. (ii). Automorphic number: An automorphic number is the number which is contained in the last digit(s) of its square. Example: 25 is an automorphic number as its square is 625 and 25 is present as the last two digits.

27. Write a menu driven program to accept a number from the user and check whether it is a BUZZ number or to accept any two numbers and to print the GCD of them.

1. (1). A BUZZ number is the number which either ends with 7 or is divisible by 7.


2. (2). GCD (Greatest Common Divisor) of two integers is calculated by continued division method. Divide the larger number by the smaller; the remainder then divides the previous divisor. The process is repeated till the remainder is zero. The divisor then results the GCD.

28. Write a program to read the number x using the Scanner class and compute the series:

Sum = x/2 + x/5 + x/8 + x/11+ ..... + x/20

The output should look like as shown below:

Enter the value of x: 10
Sum of the series is: 10.961611917494269

29. Write a program in Java to compute and display factorial of numbers up to a number entered via the Scanner class. The output should look like as shown below when 7 is input.

Enter a number: 7
1! (=1) = 1
2! (= 1 x 2) = 2
3! (= 1 x 2 x 3) = 6
4! (= 1 x 2 x 3 x 4) = 24
5! (= 1 x 2 x 3 x 4 x 5) = 120
6! (= 1 x 2 x 3 x 4 x 5 x 6) = 720
7! (= 1 x 2 x 3 x 4 x 5 x 6 x 7) = 5040

30 (i). Write a program in Java to find the sum of the given series:

x¹ + x² + x³ + x⁴ + ..... + xⁿ

30(ii). Write a program in Java to find the sum of the given series:

x¹ - x² + x³ - x⁴ + ..... - xⁿ , where x = 3

30(iii). Write a program in Java to find the sum of the given series:

\[ \frac{1}{x^{1}} + \frac{2}{x^{2}} + \frac{3}{x^{3}} + \cdots + \frac{n}{x^{n}} \]

30(iv). Write a program in Java to find the sum of the given series:

30(v). Write a program in Java to find the sum of the given series:

30(vi). Write a program in Java to find the sum of the given series:

30(vii). Write a program in Java to find the sum of the given series:

30(viii). Write a program in Java to find the sum of the given series:

30(ix). Write a program in Java to find the sum of the given series:

      1 + 3 + 7 + 15 + 31 + ..... + (2²⁰ - 1)

30(x). Write a program in Java to find the sum of the given series:

      1 * 2 * 4 * 8 * ..... * 2²⁰

31. Write a menu driven class to accept a number from the user and check whether it is Palindrome or a Perfect number.

1. (1). Palindrome number: A number is a Palindrome which when read in reverse order is same as read in the right order Example: 11, 101, 151, etc.


2. (2). Perfect number: A number is called Perfect if it is equal to the sum of its factors other than the number itself.
   Example: 6 = 1 + 2 + 3

32. Write a program to print the sum of negative numbers, sum of positive even numbers and sum of positive odd numbers from a list of n numbers entered by the user. The program terminates when the user enters a zero.