In Java, an enumeration is a special kind of class that represents a fixed number of predefined values. The values are defined as enum constants, which are static and final fields of the enumeration.

When you define an enum, you can also define a constructor for it, which is called when each enum constant is created. The constructor is passed the values of the constant's fields and can use those values to initialize the constant.

Here's an example of an enumeration called Size with a constructor that takes a single String argument:

In this example, the Size enumeration has four constants: SMALL, MEDIUM, LARGE, and EXTRA_LARGE. Each constant has an associated abbreviation, which is passed to the constructor when the constant is created. The constructor sets the value of the abbreviation field to the passed-in value.

You can call the constructor explicitly or it will be called automatically when enum constants are created, so the following code:

Size s = Size.SMALL;

is equivalent to

Size s = new Size("S");

When you define constructors for your enum, it is a best practice to make them private. So that no other classes can create an instance of your Enum. This way you can only use the predefined values of the Enum and not create any new value on runtime.

 In JavaServer Pages (JSP), the JSTL (Java Standard Tag Library) provides a set of tags that you can use to perform common tasks, such as iterating over a collection of data, performing conditional logic, and formatting text. The JSTL if tag is used to perform conditional logic in a JSP page. The if tag evaluates a boolean expression, and if the expression evaluates to true, the content inside the if tag is rendered to the response. If the expression evaluates to false, the content inside the if tag is not rendered.

JSTL (JavaServer Pages Standard Tag Library) is a collection of tags that provide common functionality when working with JSPs (JavaServer Pages). One of the tags provided by JSTL is the <c:if> tag, which can be used to conditionally include content in a JSP based on a Boolean expression.

Here's an example of how you might use the JSTL if tag to conditionally render content in a JSP page:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<c:if test="${someCondition}">

  <p>This content will be displayed if someCondition is true</p>

</c:if>

#include <stdio.h>

int main() {

    int i;

The first line includes the standard input/output header file, which is needed for the printf function used later in the program.

The main function is the entry point for the program. It is the first function that is executed when the program runs.

The next line declares a variable i of type int. This variable will be used as the loop counter in the for loop.

    for (i = 1; i <= 10; i++) {

        printf("2 * %d = %d\n", i, 2 * i);

    }

This is the for loop. It starts with the for keyword, followed by parentheses that contain three statements separated by semicolons:

The initialization statement i = 1 sets the value of i to 1 before the loop starts.

The loop condition i <= 10 specifies that the loop will continue as long as the value of i is less than or equal to 10.

The iteration statement i++ increments the value of i by 1 after each iteration of the loop.

Inside the loop, the printf function is used to print a string to the console. The string contains two %d format specifiers, which are placeholders for two integer values that will be printed. The first %d is replaced by the value of i, and the second %d is replaced by the result of 2 * i. The \n at the end of the string is a newline character that causes the output to be printed on a new line.

Finally, the return 0; statement at the end of the main function indicates that the program has completed successfully.

C program that finds the largest element in an array :

• This program first reads in n, the number of elements in the array. It then reads in n elements from the user and stores them in the array. 
• Finally, it iterates through the array and compares each element to the first element (which is initially set to the largest). 
• If it finds a larger element, it updates the value of the first element to be the larger value. At the end, the program prints out the largest element in the array.

Here is a simple program that prints out the first n numbers in the Fibonacci series in C:

Introduction to C

• First we should write the values in the memory.
• Move those values into the registers.(registers are also a kind of memory where the CPU can perform operation on the values stored in the registers.)
• Add the values in the registers.
• Save the result in the register to the memory.