**Course Title:** Mastering TypeScript: From Basics to Advanced Applications **Section Title:** Control Structures and Functions **Topic:** Loops: for, while, and forEach. Loops are an essential part of any programming language, allowing you to execute a block of code repeatedly until a specific condition is met. In this topic, we will explore the different types of loops available in TypeScript, including for loops, while loops, and forEach loops. ### For Loops A for loop is used to iterate over a block of code for a specified number of times. The syntax of a for loop in TypeScript is as follows: ```typescript for (initializer; condition; incrementer) { // code to be executed } ``` * `initializer`: This is the starting point of the loop. It is used to initialize the loop variable. * `condition`: This is the condition that determines when the loop should terminate. The loop continues to execute as long as the condition is true. * `incrementer`: This is used to update the loop variable after each iteration. Example: ```typescript // Using for loop to print numbers from 0 to 9 for (let i = 0; i <= 9; i++) { console.log(i); } ``` This code will output the numbers from 0 to 9. ### While Loops A while loop is used to execute a block of code as long as a specified condition is true. The syntax of a while loop in TypeScript is as follows: ```typescript while (condition) { // code to be executed } ``` * `condition`: This is the condition that determines when the loop should terminate. The loop continues to execute as long as the condition is true. Example: ```typescript // Using while loop to print numbers from 0 to 9 let i = 0; while (i <= 9) { console.log(i); i++; } ``` This code will also output the numbers from 0 to 9. ### forEach Loops A forEach loop is used to iterate over arrays or collections in TypeScript. The syntax of a forEach loop is as follows: ```typescript array.forEach((element) => { // code to be executed }); ``` * `array`: This is the array or collection that you want to iterate over. * `element`: This is the current element being processed in the array. Example: ```typescript // Using forEach loop to print elements of an array const numbers = [1, 2, 3, 4, 5]; numbers.forEach((number) => { console.log(number); }); ``` This code will output the elements of the numbers array. ### Key Concepts to Remember * For loops are useful when you know the number of iterations in advance. * While loops are useful when you don't know the number of iterations in advance. * forEach loops are useful for iterating over arrays or collections. ### Practical Takeaways * Use for loops when you need to execute a block of code for a specified number of times. * Use while loops when you need to execute a block of code as long as a specified condition is true. * Use forEach loops when you need to iterate over arrays or collections. ### Resources for Further Learning * [MDN Documentation on Loops and Iteration](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Loops_and_iteration) (Note that although this is a JavaScript resource, the concepts also apply to TypeScript) * [The official TypeScript documentation on loops](https://www.typescriptlang.org/docs/handbook/2/loops.html)