Multiple and/or conditions in a java while loop Ask Question Asked 7 years ago Modified 7 years ago Viewed 5k times 0 I want the while loop to execute when the user's input is a non-integer value, an integer value less than 1, or an integer value greater than 3. Predicate is passed as an argument to the filter () method. rev2023.3.3.43278. You need to change || to && so that both conditions must be true to enter the loop. Want to improve this question? In addition to while and do-while, Java provides other loop constructs that were not covered in this article. Why is there a voltage on my HDMI and coaxial cables? Linear regulator thermal information missing in datasheet. Again, remember that functional programmers like recursion, and so while loops are . a variable (i) is less than 5: Note: Do not forget to increase the variable used in the condition, otherwise We first initialize a variable num to equal 0. The second condition is not even evaluated. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. The loop repeats itself until the condition is no longer met, that is. The Java while Loop. Java while loop is a control flow statement that allows code to be executed repeatedly based on a given Boolean condition. In our example, the while loop will continue to execute as long as tables_in_stock is true. Based on the result of the evaluation, the loop either terminates or a new iteration is started. To illustrate this idea, lets have a look at a simple guess my name game. In the body of the while loop, the panic is increased by multiplying the rate times the minute and adding to the total. How can I use it? A while loop is a control flow statement that allows us to run a piece of code multiple times. A nested while loop is a while statement inside another while statement. Thankfully, many developer tools (such as NetBeans for Java), allow you to debug the program by stepping through loops. First of all, let's discuss its syntax: while (condition (s)) { // Body of loop } 1. In this tutorial, we learn to use it with examples. ?` unparenthesized within `||` and `&&` expressions, SyntaxError: for-in loop head declarations may not have initializers, SyntaxError: function statement requires a name, SyntaxError: identifier starts immediately after numeric literal, SyntaxError: invalid assignment left-hand side, SyntaxError: invalid regular expression flag "x", SyntaxError: missing ) after argument list, SyntaxError: missing ] after element list, SyntaxError: missing } after function body, SyntaxError: missing } after property list, SyntaxError: missing = in const declaration, SyntaxError: missing name after . The condition is evaluated before when we do not use the condition in while loop properly. Hello WorldIf elseFor loopWhile loopPrint AlphabetsPrint Multiplication TableGet Input From UserAdditionFind Odd or EvenFahrenheit to celsius Java MethodsStatic BlockStatic MethodMultiple classesJava constructor tutorialJava exception handling tutorialSwappingLargest of three integersEnhanced for loopFactorialPrimesArmstrong numberFloyd's triangleReverse StringPalindromeInterfaceCompare StringsLinear SearchBinary SearchSubstrings of stringDisplay date and timeRandom numbersGarbage CollectionIP AddressReverse numberAdd MatricesTranspose MatrixMultiply MatricesBubble sortOpen notepad. This will be our loop counter. "while" works fine by itself. Multiple conditions for a while loop [closed] Ask Question Asked 1 year, 11 months ago Modified 1 year, 11 months ago Viewed 3k times 3 Closed. This type of while loop is called an indefinite loop, because it's a loop where you don't know when the condition will be true. If your code, if the user enters 'X' (for instance), when you reach the while condition evaluation it will determine that 'X' is differente from 'n' (nChar != 'n') which will make your loop condition true and execute the code inside of your loop. The while loop loops through a block of code as long as a specified condition evaluates to true. Our while loop will run as long as the total panic rate is less than 100%, which you can see in the code here: The code sets a static rate of panic at .02 (2%) and total panic to 0. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); James Gallagher is a self-taught programmer and the technical content manager at Career Karma. 3. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Java while loop with Examples - GeeksforGeeks In this example, we will use the random class to generate a random number. The while loop is used to iterate a sequence of operations several times. The dowhile loop executes the block of code in the do block once before checking if a condition evaluates to true. Instead of having to rewrite your code several times, we can instead repeat a code block several times. How can this new ban on drag possibly be considered constitutional? The while statement continues testing the expression and executing its block until the expression evaluates to false.Using the while statement to print the values from 1 through 10 can be accomplished as in the . Each value in the stream is evaluated to this predicate logic. The Java while loop is a control flow statement that executes a part of the programs repeatedly on the basis of given boolean condition. Introduction. Furthermore, in this example, we print Hello, World! the loop will never end! We are sorry that this post was not useful for you! Java While Loop - Tutorial With Programming Examples Java 8 Streams Filter With Multiple Conditions Examples For multiple statements, you need to place them in a block using {}. succeed. Recovering from a blunder I made while emailing a professor. This lesson has provided the syntax for the Java while statement, including some code examples. Heres an example of an infinite loop in Java: This loop will run infinitely. Making statements based on opinion; back them up with references or personal experience. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. If you do not remember how to use the random class to generate random numbers in Java, you can read more about it here. It works well with one condition but not two. The below flowchart shows you how java while loop works. It may sound kind of funny, but in real-world applications the consequences can be severe: whole systems are brought down or data can be corrupted. We only have the capacity to make five tables, after which point people who want a table will be put on a waitlist. The while loop loops through a block of code as long as a specified condition is true: Syntax Get your own Java Server while (condition) { // code block to be executed } In the example below, the code in the loop will run, over and over again, as long as a variable (i) is less than 5: Example Get your own Java Server I think that your problem is that you use scnr.nextInt() two times in the same while. Why does Mister Mxyzptlk need to have a weakness in the comics? This is the standard input stream which in most cases corresponds to keyboard input. . - Definition, History & Examples, Stealth Advertising: Definition & Examples, What is Crowdsourcing? ({ /* */ }) to group those statements. An error occurred trying to load this video. After the first run-through of the loop body, the loop condition is going to be evaluated for the second time. Inside the loop body, the num variable is printed out and then incremented by one. Add details and clarify the problem by editing this post. Just remember to keep in mind that loops can get stuck in an infinity loop so that you pay attention so that your program can move on from the loops. I highly recommend you use this site! evaluates to true, statement is executed. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The while loop runs as long as the total panic is less than 1 (100%). You forget to declare a variable used in terms of the while loop. How to fix java.lang.ClassCastException while using the TreeMap in Java? Difference between while and do-while loop in C, C++, Java, Difference between for and do-while loop in C, C++, Java, Difference between for and while loop in C, C++, Java, Java Program to Reverse a Number and find the Sum of its Digits Using do-while Loop, Java Program to Find Sum of Natural Numbers Using While Loop, Java Program to Compute the Sum of Numbers in a List Using While-Loop, Difference Between for loop and Enhanced for loop in Java. The computer will continue to process the body of the loop until it reaches the last line. This means the while loop executes until i value reaches the length of the array. If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail: W3Schools is optimized for learning and training. Programming - While Loop - University of Utah In a guessing game we would like to prompt the player for an answer at least once and do it until the player guesses the correct answer. What is the difference between public, protected, package-private and private in Java? First, we import the util.Scanner method, which is used to collect user input. The program will thus print the text line Hello, World! Update Expression: After executing the loop body, this expression increments/decrements the loop variable by some value. In our case 0 < 10 evaluates to true and the loop body is executed. What is \newluafunction? Two months after graduating, I found my dream job that aligned with my values and goals in life!". This tutorial will discuss the basics of the while and dowhile statements in Java, and will walk through a few examples to demonstrate these statements in a Java program. How to tell which packages are held back due to phased updates. Example 1: This program will try to print Hello World 5 times. If the number of iterations not is fixed, its recommended to use a while loop. When compared to for loop, while loop does not have any fixed number of iteration. The following code example loops through numbers up to 1,000 and returns all even values: The code creates an integer and sets the value to 1. Read User Input Until a Condition is Met | Baeldung Syntax : while (boolean condition) { loop statements. } Use //# instead, TypeError: can't assign to property "x" on "y": not an object, TypeError: can't convert BigInt to number, TypeError: can't define property "x": "obj" is not extensible, TypeError: can't delete non-configurable array element, TypeError: can't redefine non-configurable property "x", TypeError: cannot use 'in' operator to search for 'x' in 'y', TypeError: invalid 'instanceof' operand 'x', TypeError: invalid Array.prototype.sort argument, TypeError: invalid assignment to const "x", TypeError: property "x" is non-configurable and can't be deleted, TypeError: Reduce of empty array with no initial value, TypeError: setting getter-only property "x", TypeError: X.prototype.y called on incompatible type, Warning: -file- is being assigned a //# sourceMappingURL, but already has one, Warning: 08/09 is not a legal ECMA-262 octal constant, Warning: Date.prototype.toLocaleFormat is deprecated, Warning: expression closures are deprecated, Warning: String.x is deprecated; use String.prototype.x instead, Warning: unreachable code after return statement. Add Answer . Whatever you can do with a while loop can be done with a for loop or a do-while loop. Its like a teacher waved a magic wand and did the work for me. I would definitely recommend Study.com to my colleagues. The final iteration begins when num is equal to 9. If the user has guessed the wrong number, the contents of the do loop run again; if the user has guessed the right number, the dowhile loop stops executing and the message Youre correct! to true. It is possible to set a condition that the while loop must go through the code block a given number of times. If the Boolean expression evaluates to true, the body of the loop will execute, then the expression is evaluated again. A body of a loop can contain more than one statement. We only have five tables in stock. This condition uses a boolean, meaning it has a yes/no, true/false, or 0/1 value. These loops are similar to conditional if statements, which are blocks of code that only execute if a specific condition evaluates to true. And if youre interested enough, you can have a look at recursion. We then define two variables: one called number which stores the number to be guessed, and another called guess which stores the users guess. While Loop Java: A Complete Guide | Career Karma While that number is not equal to 12, the currently generated random number should be printed, as well as how far the current number is from 12 in absolute numbers. However, the loop only works when the user inputs a non-integer value. What the Difference Between Cross-Selling & Upselling? While loop in Java comes into use when we need to repeatedly execute a block of statements. If Statements, Loops and Recursions OCaml Tutorials Is there a single-word adjective for "having exceptionally strong moral principles"? Each iteration, the loop increments n and adds it to x. In the java while loop condition, we are checking if i value is greater than or equal to 0. Technical Problem Cluster First Answered On December 21, 2020 Popularity 9/10 Helpfulness 4/10 Contributions From The Grepper Developer Community. In this example, we have 2 while loops. Multiple and/or conditions in a java while loop, How Intuit democratizes AI development across teams through reusability. Can I tell police to wait and call a lawyer when served with a search warrant? The while statement creates a loop that executes a specified statement It consists of the while keyword, the loop condition, and the loop body. How Intuit democratizes AI development across teams through reusability. For example, if you want to continue executing code until the user hits a specific key or a specified threshold is reached, you would use a while loop. How do I read / convert an InputStream into a String in Java? In the loop body we receive input from the player and then the loop condition checks whether it is the correct answer or not. Share Improve this answer Follow forever. as long as the test condition evaluates to true. Next, it executes the inner while loop with value j=10. The while loop is considered as a repeating if statement. All other trademarks and copyrights are the property of their respective owners. How do I generate random integers within a specific range in Java? - Definition & Examples, Strategies for Effective Consumer Relations, Cross-Selling in Retail: Techniques & Examples, Sales Mix: Definition, Formula & Variance Analysis. First, We'll start by looking at how to apply the single filter condition to java streams. Overview When we write Java applications to accept users' input, there could be two variants: single-line input and multiple-line input. Connect and share knowledge within a single location that is structured and easy to search. The expression that the loop will evaluate. In this tutorial, we learn to use it with examples. How do I break out of nested loops in Java? In general, it can be said that a while loop in Java is a repetition of one or more sequences that occurs as long as one or more conditions are met. Enable JavaScript to view data. This tutorial discussed how to use both the while and dowhile loop in Java. Lets say we are creating a program that keeps track of how many tables are in-stock. Here the value of the variable bFlag is always true since we are not updating the variable value. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. This means repeating a code sequence, over and over again, until a condition is met. SyntaxError: test for equality (==) mistyped as assignment (=)? Please leave feedback and help us continue to make our site better. I am a PL-SQL developer and I find it difficult to understand this concept. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? Loops in Java | Java For Loop (Syntax, Program, Example) - Javatpoint Since we are incrementing i value inside the while loop, the condition i>=0 while always returns a true value and will execute infinitely. But it does not work. This is why in the output you can see after printing i=1, it executes all j values starting with j=10 until j=5 and then prints i values until i=5. operator, SyntaxError: redeclaration of formal parameter "x". Our loop counter is printed out the last time and is incremented to equal 10. All rights reserved. The outer while loop iterates until i<=5 and the inner while loop iterates until j>=5. This article covered the while and do-while loops in Java. This means repeating a code sequence, over and over again, until a condition is met. He is an adjunct professor of computer science and computer programming. Sometimes its possible to use a recursive function instead of loops. Instead of having to rewrite your code several times, we can instead repeat a code block several times. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 2. The Java do while loop is a control flow statement that executes a part of the programs at least . shell script - Multiple conditions for a while loop - Unix & Linux Your condition is wrong. By continuing you agree to our Terms of Service and Privacy Policy, and you consent to receive offers and opportunities from Career Karma by telephone, text message, and email. This code will run forever, because i is 0 and 0 * 1 is always zero. - the incident has nothing to do with me; can I use this this way? Then, we declare a variable called orders_made that stores the number of orders made. This loop will is executed before the condition is tested: Do not forget to increase the variable used in the condition, otherwise A while statement performs an action until a certain criteria is false. Use myChar != 'n' && myChar != 'N' instead. For Loop For-Each Loop. If the number of iterations not is fixed, it's recommended to use a while loop. Asking for help, clarification, or responding to other answers. Now the condition returns false and hence exits the java while loop. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? The whileloop continues testing the expression and executing its block until the expression evaluates to false. We want our user to first be asked to enter a number before checking whether they have guessed the right number. test_expression This is the condition or expression based on which the while loop executes. will be printed to the console, and the break statement is executed. The Java while loop exist in two variations. Our program then executes a while loop, which runs while orders_made is less than limit. Note that the statement could also have been written in this much shorter version of the code: There's a test within the while loop that checks to see if a number is even (evenly divisible by 2); it then prints out that number. While loops in OCaml are written: while boolean-condition do expression done. So that = looks like it's a typo for === even though it's not actually a typo. It then again checks if i<=5. Since the condition j>=5 is true, it prints the j value. The syntax for the while loop is similar to that of a traditional if statement. Before each iteration, the loop condition is evaluated and, just like with if statements, the body is executed only if the loop condition evaluates to true. Here we are going to print the even numbers between 0 and 20. Example 2: This program will find the summation of numbers from 1 to 10. Get Matched. The while loop is considered as a repeating if statement. class BreakWhileLoop { public static void main(String[] args) { int n; Scanner input = new Scanner(System.in); while (true) { // Condition in while loop is always true here System.out.println("Input an integer"); n = input.nextInt(); if (n == 0) { break; } System.out.println("You entered " + n); } }}, class BreakContinueWhileLoop { public static void main(String[] args) { int n; Scanner input = new Scanner(System.in); while (true) { System.out.println("Input an integer"); n = input.nextInt(); if (n != 0) { System.out.println("You entered " + n); continue; } else { break; } } }}. Lets take a look at a third and final example. Furthermore, in this case, it will not be easy to print out what the answer will be since we get different answers every time. If the user enters the wrong number, they should be promoted to try again. A while loop will execute commands as long as a certain condition is true. For the Nozomi from Shinagawa to Osaka, say on a Saturday afternoon, would tickets/seats typically be available - or would you need to book? 10 is not smaller than 10. Nested While Loops in Java - Video & Lesson Transcript - Study.com In Java, a while loop is used to execute statement (s) until a condition is true. while - JavaScript | MDN - Mozilla A while loop is a control flow statement that runs a piece of code multiple times. Consider the following example, which iterates over a document's comments, logging them to the console. Take note of the statement 'minute++' in the body of the while loop: It was placed after the calculation for panic. Like loops in general, a while loop can be used to repeat an action as long as a condition is met. For example, you can continue the loop until the user of the program presses the Z key, and the loop will run until that happens. An expression evaluated before each pass through the loop. After this code has executed, the dowhile loop evaluates whether the number the user has guessed is equal to the number the user is to guess. Iteration 1 when i=0: condition:true, sum=20, i=1, Iteration 2 when i=1: condition:true, sum=30, i=2, Iteration 3 when i=2: condition:true, sum =70, i=3, Iteration 4 when i=3: condition:true, sum=120, i=4, Iteration 5 when i=4: condition:true, sum=150, i=5, Iteration 6 when i=5: condition:false -> exits while loop.