5+ While 使い方 Ideas

During vs. While Is During a Preposition? • 7ESL from 7esl.com

Introduction

When it comes to programming, loops are an essential component. They allow a program to execute a set of instructions repeatedly until a certain condition is met. The while loop is one of the most fundamental types of loops in programming. In this article, we will explore the various ways to use the while loop in your code.

What is a while loop?

A while loop is a control flow statement that allows a program to repeatedly execute a set of statements as long as a particular condition is true. The syntax for a while loop is as follows:

 while (condition) { }

The condition is evaluated before each iteration of the loop. If the condition is true, the statements inside the loop are executed. This process continues until the condition becomes false.

Using while loops in your code

While loops can be used in a variety of ways in your code. Here are some common use cases:

1. Iterating over a collection

One common use case for a while loop is to iterate over a collection of items. For example, suppose you have an array of numbers and you want to print each number to the console. You could use a while loop to iterate over the array as follows:

 let numbers = [1, 2, 3, 4, 5]; let i = 0; while (i < numbers.length) { console.log(numbers[i]); i++; }

This code will print each number in the array to the console.

2. Waiting for user input

Another use case for a while loop is to wait for user input. For example, suppose you want to prompt the user to enter a number and keep prompting them until they enter a valid number. You could use a while loop as follows:

 let number = NaN; while (isNaN(number)) { number = parseInt(prompt("Enter a number:")); } console.log("The number is " + number);

This code will keep prompting the user to enter a number until they enter a valid number.

3. Implementing game logic

While loops are also useful for implementing game logic. For example, suppose you are creating a game where the player has to guess a number. You could use a while loop to keep prompting the player for guesses until they guess the correct number. Here is an example:

 let secretNumber = Math.floor(Math.random() * 100) + 1; let guess = NaN; while (guess !== secretNumber) { guess = parseInt(prompt("Guess the secret number (between 1 and 100):")); if (guess < secretNumber) { console.log("Too low!"); } else if (guess > secretNumber) { console.log("Too high!"); } } console.log("Congratulations, you guessed the secret number!");

This code will keep prompting the player for guesses until they guess the correct number.

Conclusion

The while loop is an essential component of programming. It allows a program to repeatedly execute a set of statements as long as a particular condition is true. There are many ways to use while loops in your code, including iterating over a collection, waiting for user input, and implementing game logic. By mastering the art of while looping, you can create more robust and efficient code.