### Java Practice Problems

Learning to program means learning how to solve problems using code. Conceptually it is not very difficult to write a program that solves a problem that you can solve yourself. The skill you need to acquire is thinking very precisely about how you solve the problem and breaking it down into steps that are so simple that a computer can execute them
This Section contains a lot Programs for practice.

#### Assignment - Looping

There are number of program to practice .List are given below-

WAP to print numbers from 1 to 100.

WAP to print the factors of a Number.

WAP to print the Even Factors of the Number.

WAP to print the Odd factors of a Number.

WAP to print the sum of even factors of a Number.

WAP to input a number and check whether it is perfect number or not.
A perfect number is a number which is equal to sum of its factors excluding itself.
example:
6 is prefect number.
6=1+2+3

WAP to input a number and check whether it is prime number or not. Prime numbers are the number which has only two factors one and itself.
example:
7 is prime number .Factors of 7 are 1 and 7.

WAP to find the HCF and LCM of two numbers.
The Highest Common Factor (H.C.F) of two (or more) numbers is the largest number that divides evenly into both numbers. In other words the H.C.F is the largest of all the common factors.

WAP to count the number of digits of number.
Input- 456
Ouput:-3

WAP to input a number and check whether it is palindrome number or not. Palindrome Number: Number=reverse of a number
Input- 456
Ouput:-3

WAP to input a number and find the sum of first and last digit of number.
Input- 456
Ouput:-4+6=10

WAP to input a number and check whether it is Armstrong Number or Not
Armsrong Number: Sum of cube of each digit of a number =Original number

WAP to input a number and check whether it is Special Number or Not
Special Number: Sum of factorial of each digit of a number =Original number

#### Write a program to print series ...

Program for printing the series...

1,2 3, 4 ..................................up to 10

1 , 2 , 5 , 7 ,...............................................upto 20 terms

1, 2, 4, 8, 16 .............................up to 30 terms.

1, 5, 25, 125,............................ up-to 20 terms.

100 , 97, 94, 91.......................................up-to 10

1+2+3+4.....................................up-to 20 terms.

1+7+13+19...........................up-to 25 terms.

#### Assignment -Pattern

Write a program for printing different type of pattern given below

Pattern 1) Pattern 2) Pattern 3) Pattern 4) Pattern 5) Pattern 6) #### Assignment - Arrays

This assignment contains different types of question on Arrays(1D and 2D).

``````/*This program shows how we take input from user
and put the elements in 1D array.
and then print using for loop and for-each loop
*/

import java.util.Scanner;

class Example {

public static void main(String[] args) {
//printing the message on console
System.out.println("Enter the size of array");
//we have to use java.util.Scanner for taking the size from the keyboard.
//We can also use other ways to take input from a user.
Scanner ob = new Scanner(System.in);
int size = ob.nextInt();
//declearing array of size 'size'
int a[] = new int[size];
//taking  input from user and filling to array using for-loop
for (int i = 0; i < size; i++) {
a[i] = ob.nextInt();
}
//now perform stuff on array

//now printing the elements of array using normal for loop
System.out.println("printing array using for-loop");
for (int i = 0; i < size; i++) {
System.out.print(a[i] + "\t");
}

System.out.println();

System.out.println("printing array using for-each loop");
//printing the elements of array using for-each loop
for (int i : a) {
System.out.print(i + " ");
}

}

}
``````
```Enter the size of array
5
12 65 34 87 34
printing array using for-loop
12      65      34      87      34
printing array using for-each loop
12 65 34 87 34```

WAP to input 10 numbers in an array and print the sum of all the numbers

WAP to input 10 numbers in an array and print the sum of all odd numbers.

WAP to input 10 numbers in an array and print the sum of all even numbers.

WAP to input 10 numbers in an array and print the sum of all the numbers at even position .

WAP to input 10 numbers in an array and print the sum of all the numbers at oddposition .

WAP to input 10 numbers in an array and print the sum of all the odd numbers at odd position .

WAP to input 'n' numbers in an array and print the count of all odd numbers.

WAP to input 'n' numbers in an array and print the count of all even numbers.

WAP to input 'n' numbers in an array and find the average.

WAP to input 'n' numbers in an array and find the average of all odd numbers in an array. .

WAP to input 'n' numbers in an array and find the largest number along with its position..

WAP to input 'n' numbers in an array and find the smallest number along with its position..

WAP to input 'n' numbers in an array and sort the elements using any sorting technique..

WAP to input 'n' numbers in an array and remove the duplicate elements and then print the elements of array. 