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Programming languages have different structures that enable developers to write efficient code. In this technical documentation, we will discuss four essential structures that are commonly used in many programming languages: variables, functions, loops, and conditionals.

Variables

Variables are used to store and manipulate data in programming. In most programming languages, variables have to be declared before they are used. Here are some key points about variables:

To declare a variable, we use the var, let, or const keyword, followed by the variable name and an optional assignment operator (=) to assign a value to the variable.
Variables can hold different types of data, such as numbers, strings, and booleans.
We can change the value of a variable during runtime.
Variables can be used to hold the results of expressions or to pass data between functions.

Here's an example of how to declare and use a variable in JavaScript:

let num1 = 5;
let num2 = 10;
let result = num1 + num2;
console.log(result); // Output: 15

Functions

Functions are reusable blocks of code that can be called multiple times in a program. They help in writing modular and maintainable code. Here are some key points about functions:

Functions are defined using the function keyword, followed by the function name and parentheses that can contain one or more parameters.
The code inside a function is executed when the function is called.
Functions can return values using the return keyword.
Functions can be called with or without arguments.

Here's an example of a function in JavaScript that adds two numbers:

function addNumbers(num1, num2) {
            

              return num1 + num2;

        }
        

        

        let result = addNumbers(5, 10);
        

        console.log(result); // Output: 15

Loops

Loops are used to execute a block of code repeatedly. They are useful for iterating over arrays and objects, and for performing tasks that need to be repeated multiple times. Here are some key points about loops:

There are different types of loops, such as for, while, and do-while.
Loops have a loop condition that is checked before each iteration.
Loops can use the break keyword to exit the loop early, and the continue keyword to skip an iteration.

Here's an example of a for loop in JavaScript that iterates over an array and prints its elements:

let array = [1, 2, 3, 4, 5];
            

            

        for (let i = 0; i < array.length; i++) { 
            
   console.log(array[i]);
            
}

Conditionals

Conditionals are used to execute code based on a condition. They are useful for making decisions and branching the program's flow. Here are some key points about conditionals:

There are different types of conditionals, such as if, else, and switch.
Conditionals use comparison and logical operators to evaluate conditions.
Conditionals can have multiple conditions using logical operators like && (and) and || (or).
Conditionals can use the else keyword to execute code if the condition is false.

Here's an example of an if statement in JavaScript that checks if a number is positive or negative:

let num=5;
                

                
if (num > 0) {
                
  console.log("The number is positive");
                
} else {
                
  console.log("The number is negative");
                
}