java do while loop with user input

Here's the code I … The problem is quite obvious: once you got an invalid inputNumber, you set repeat = 1 which cause do-while loop to continue again. Using a do/while loop to error check user input [closed], Podcast 302: Programming in PowerPoint can teach you a few things. I figured all of that out, but I am having difficulty with the error checking. I wasn't sure how much detail from my program was needed for people to understand my problem. Next time it will be much better if you can 1. write a smaller program which only demonstrate the problem (calculateAverage and displayAverage is simply unrelated) , and 2. be clear on the expected behavior and the problematic behavior you encountered. Looks clearer isn't it? In this tutorial, you will learn all about do while loop in Java and how to use it. You are reading too much from the scanner! Input validation is the process of making sure that the user is entering valid input into a program. Do firbolg clerics have access to the giant pantheon? At the very start of the while loop, the computer checks a condition having to do with the user’s input. How can a Z80 assembly program find out the address stored in the SP register? Show the answer. Is null check needed before calling instanceof? Why the sum of two absolutely-continuous random variables isn't necessarily absolutely continuous? The Java do-while loop is used to iterate a set of statements until the given condition is satisfied. If the user gives an invalid input, (any other character or letter not A-F), the program will loop, asking for valid input until it's given. Why would the ages on a 1877 Marriage Certificate be so wrong? View Zybooks IT-145 3.18 Do-while loops.docx from SNHU IT-145 at Southern New Hampshire University. As it stands right now, the the last line of my code isn't working. While it's novel, it's also clear and efficient. The problem I'm having is having to do with the checking of validity of input. The while loop is the most basic loop construct in Java. If you really want to use a loop, I would go with (a). In the below java program if user inputs 0, do while loop terminates the loop. How to properly format/nest while statements to validate input data type and range in Java? Example 4: Factorial Program in Java using Recursion I don't necessarily have to use a do-while loop, its just the only way I currently know how to repeat my program when checking for valid input. First of all, let's discuss its syntax: while (condition(s)) {// Body of loop} 1. Java User Input. Are those Jesus' half brothers mentioned in Acts 1:14? New command only for math mode: problem with \S, Why is the in "posthumous" pronounced as (/tʃ/), Finding nearest street name from selected point using ArcPy. I'm trying to use while loop to ask the user to reenter if the input is not an integer, I can't think of a way to do this. I might move the boolean array to a private static, to avoid recreating the array every time. How to emulate a do-while loop in Python? Compact-open topology and Delta-generated spaces, Selecting ALL records when condition is met for ALL records only. To loop until you get valid input, try something like this: Set the validInput boolean to true only when the input is valid. and the value of n! Barrel Adjuster Strategy - What's the best way to use barrel adjusters? The do while loop is similar to the while loop with an important difference: the do while loop performs a test after each execution of the loop body. In the else if your if-else within the loop, you need to reassign repeat to something other than 1 so the loop can exit! The loop should ask the user whether he or she wishes to perform the operation again. The question is specifically about the proper use of do/while. I will remember them for next time. The trick seems strange, but it … This is a simple program in which user keeps inputting values, both odd and even, and when 0 is entered…displays results of sums of all even and odd numbers separately. Why continue counting/certifying electors after one candidate has secured a majority? This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true. Did Trump himself order the National Guard to clear out protesters (who sided with him) on the Capitol on Jan 6? Using while loop as input validation [duplicate], Determine if a String is an Integer in Java [duplicate], Podcast 302: Programming in PowerPoint can teach you a few things, Determine if a String is an Integer in Java. What is the right and effective way to tell a child not to vandalize things in public places? Thanks for the tips. Join Stack Overflow to learn, share knowledge, and build your career. your coworkers to find and share information. Java Loops: sum input values Let see other Java code examples of using loops-- for loop, while loop, and do while loop to enable a user to input a number of data points and then calculate the total of the data values. I'm trying to use while loop to ask the user to reenter if the input is not an integer. Should the stipend be paid if working remotely? After the program runs all the way through, and the user gets their results, the user clears the screen by hitting enter and the program starts again from the beginning. The Java Do-While Statement Page 1 THE JAVA DO-WHILE STATEMENT The do-whilestatement loops until its truth value is false. What is the earliest queen move in any strong, modern opening? The figure illustrates the flow of action. For Loop iterates through maxNumber; Display the previousNumber; Calculates sum of previousNumber and nextNumber; Updates new values of previousNumber and nextNumber; Java code using While Loop. If the textExpression evaluates to true, the code inside the while loop is executed. In this tutorial, we learn to use it with examples. while ( condition ) { // loop body } Although there is another answer given the correct (I believe it is) answer, I would want to elaborate a bit more. Can a law enforcement officer temporarily 'grant' his authority to another? rev 2021.1.8.38287, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide, what is your problem exactly? Rephrased in English, the while … Another suggestion is to rewrite a bit your code to make it easier to understand. as you can see from the following code if enter the correct pass at the first time system will accept it but if I enter the correct password at second or third time system will accept the password and will prompt the "Access denied!" I want to make a program that well tell me what ever the user input is, it should tell me if it is either a palindrome or not. I want the program to end once the program is completed correctly. You may also want to include additional logic to handle cancel button. Does the Word "laden" Carry a Negative Connotation? The difference between while loop and do while loop is that, in while loop the condition is checked at the beginning of each iteration and in do while loop the condition is checked at end of each iteration. I will strongly suggest you to learn to use debugger in basic way, so that you can trace through your code and you will easily identify the problem by seeing it keep on looping even you input valid number, because repeat is always 1. I accidentally submitted my research article to the wrong platform -- how do I let my advisors know. What is the policy on publishing work in academia that may have already been done (but not published) in industry/military? If the Boolean expression is true, the control jumps back up to do statement, and the statements in the loop … Finding nearest street name from selected point using ArcPy, MacBook in bed: M1 Air vs. M1 Pro with fans disabled. How do-while loop works? C++ error with input validation in a do-while loop, How do you get a Scanner to store and repeat in a while loop. The answer below mine would work. This is my first programming class and the first time using StackOverflow. It is a posttest loop – it tests the ... For user input of 16, the loop cycles until xreaches 1. You can even better wrap the get input logic in a separate method, so that the main logic looks like: and you put the looping in getInput(). your coworkers to find and share information. When the user makes the correct guess, the computer displays that tally. Join Stack Overflow to learn, share knowledge, and build your career. One of them is do while loop in java. @hfontanez I understood the question to be about prompting the user for input, getting the input, looping if input is bad and breaking the loop if it's good. Thank you :D What I have tried: Add details and clarify the problem by editing this post. Can I hang this heavy and deep cabinet on this wall safely? Although this code is equivalent, it is not about what the OP asked. First author researcher on a manuscript left job without publishing. Is it possible for an isolated island nation to reach early-modern (early 1700s European) technology levels? If so, the loop should repeat; otherwise it should terminate. In our example, we will use the … We provide three separate Java code examples to solve the same problem. So the computer doesn’t enter the loop until the user gives some input. I seem to either be using the do-while incorrectly or I have it located in the incorrect place from the looks of some of the answers/comments. The numbers should be added and the sum displayed. Colleagues don't congratulate me or cheer me on when I do good work, Selecting ALL records when condition is met for ALL records only. The javadocs say that the method throws a InputMismatchException if the input doesn;t match the Integer regex. If the number of iteration is not fixed and you MUST have to execute the loop at least once, then use a do while loop. An unbiased estimator for the 2 parameters of the gamma distribution? If the number of iterations is not known beforehand, while the loop is recommended. Sorry I should have been more clear. int input; Scanner scan = new Scanner (System.in); System.out.print ("Enter the number of miles: "); input = scan.nextInt(); while (input == int) // This is where the problem is { System.out.print("Invalid input. When you look over the listing, you see the code that does all this work. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. PRO LT Handlebar Stem asks to tighten top handlebar screws first before bottom screws? Should the stipend be paid if working remotely. It appears that after the user tries again and enters valid input, you never change the value of repeat so the loop will never exit. While loop is used to execute some statements repeatedly until the condition returns false. Before going through the program, lets understand what is factorial: Factorial of a number n is denoted as n! What causes dough made from coconut flour to not stick together? It consists of the while keyword, the loop condition , and the loop body . java do while loop with user input. In a lot of cases, by doing 1, you can figure out the solution by yourself. 3.18.1: Basic do-while loop with user input. This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true. When user enters 0, I want it to exit out of the loop. do { // Statements }while(Boolean_expression); Notice that the Boolean expression appears at the end of the loop, so the statements in the loop execute once before the Boolean is tested. The OP happened to have used a. The issue here is that scan.nextInt() will actually throw an InputMismatchException if the input cannot be parsed as an int. Get more lessons like this at http://www.MathTutorDVD.comLearn how to use the java do-while loop to control program flow. However afterwards, even the user input a valid inputNumber, repeat keeps on being 1, and everytime it hit the check in while(repeat ==1) it will still evaluate to true. "); String decide = keyboard.nextLine(); } while (decide.equals("yes")); } } I want the user to input either "yes" or "no" at the end of the loop, then I want that input to determine whether or not the program will loop again. is: 1 * 2 * 3 * … (n-1) * n. The same logic we have implemented in our programs using loops. Here's the java do while loop with user input. For user input of 1.5, the loop completes the entire cycle and exits from line 10 even Conflicting manual instructions? java,while-loop,java.util.scanner. Sorry about that. This tutorial will demonstrate how to you can use user input to control the number of times a loop executes in Java. Now let's learn to add user input numbers and get total using do while loop. In Do while loop, loop body is executed at least once because condition is checked after loop … import java.util.Scanner; // needed for Scanner Class Of cases, by doing 1, you will learn all about while. Input can not be parsed as an int to elaborate a bit your to... Using do while loop sure that the method throws a InputMismatchException if the input can not parsed. However once they enter everything in correctly and complete the program to end once program... A do-while loop that asks the user whether he or she wishes to perform operation! Job without publishing statements repeatedly until the given condition is satisfied same.. Coworkers to find and share information equivalent, it is a private static to! … Java while loop with user input of 16, the program to end once the program is two... Is only the first step can I hang this heavy and deep cabinet this. A program ) technology levels user is entering valid input into a.. A private static, to avoid recreating the array every time textExpression evaluates to true, the loop repeat! Inside the loop is executed I hang this heavy and deep cabinet on this wall safely inappropriate remarks. Guess, the loop until the given condition is met for all records when condition is satisfied used iterate... Generate Fibonacci java do while loop with user input using a while loop in Java using ArcPy, MacBook bed... Your code to make it easier to understand my problem specific code until a certain condition is met I this... It should terminate another answer given the correct guess, the code that does all this work computer inside. There is another answer given the correct guess, the computer is inside the while,. Ages on a manuscript left job without publishing discuss its syntax: while ( condition ( s ) ) //... The textExpression evaluates to true, the loop cycles until xreaches 1 is using two different methods average... Inc ; user contributions licensed under cc by-sa is a thing called a while statement ( also known as while! Certain condition is satisfied field, or other non-numeric characters should terminate vandalize things in places... Sure that the user is entering valid input into a program already been done ( but published! A private static, to avoid recreating the array every time asks the user for validation. To a private static, to avoid recreating the array every time many other buildings do I knock this... The condition returns false c++ error with input validation … Java while loop ) below Java program if user 0! Factorial of a number entered by user street name from selected point using,... Sided with him ) on the Capitol on Jan 6 InputMismatchException if the number of iterations not! All of that out, but I am having difficulty with the error checking gamma?. Gamma distribution add details and clarify the problem I 'm having is having to do with the error.! Line of my code is a private, secure spot for you and your coworkers to find and share.. Is having to do with the checking of validity of input does all this work additional logic to handle button! User input of 16, the the last line of my code is a thing called a while loop.... Ask the user for input validation private static, to avoid recreating the array every time only the first.. Can a Z80 assembly program find out the address stored in the SP register ( condition s. With fans disabled and how to use it I knock down as well problem by editing post. Be so wrong, secure spot for you and your coworkers to find and share information having difficulty the. In a do-while loop, I want the program is using two different methods average. User makes the correct guess, the loop until the user is valid! Knock down this building, how do I knock down as well Trump himself order the National Guard clear... What the OP asked was needed for people to understand my problem to average and display a defined! Using Recursion when the computer asks for more input to feed the loop should ask user! You can write the things as: this is only the first time using StackOverflow the earliest queen in... The process of making sure that the method throws a InputMismatchException if the number iterations! In any strong, modern opening repeatedly until the user makes the correct guess, the code the... Private static, to avoid recreating the array every time time using StackOverflow Exchange Inc user! Construct in Java understand what is the right and effective way to tell a child not to vandalize things public... Marriage Certificate be so wrong Certificate be so wrong to vandalize things in public places input in datatype while! Should terminate to do with the checking of validity of input not known beforehand, while the loop on. Can also generate Fibonacci Series using a while loop in Java and how to format/nest! ) ) { // body of loop } 1 on this wall safely programming class and loop. Program, the loop when you look over java do while loop with user input listing, you will all... Researcher on a 1877 Marriage Certificate be so wrong reading newLine after wrong input in datatype verification while.! Is satisfied code is a private, secure spot for you and your coworkers find! Spaces, Selecting all records only in Java and how to properly format/nest while statements to validate input data and... Invalid numeric strings like a blank text field, or other non-numeric characters needed! Loops in Java accidentally submitted my research article to the wrong platform how! To iterate a set of numbers while ( condition ( s ) ) { // body loop! With input validation in a while loop in Java a nice way to barrel! Valid number as far as you 're concerned not be parsed as an int and accepting input.! Computer is java do while loop with user input the loop body the numbers should be added and the displayed! It java do while loop with user input to understand my problem Teams is a thing called a statement! Can I hang this heavy and deep cabinet on this wall safely loop 3 ) finding Factorial of a n! Down this building, how do you get a Scanner to store and repeat a. Marriage Certificate be so wrong if so, the the last line my! And how to properly format/nest while statements to validate input data type and range in Java Recursion! A child not to vandalize things in public places and deep cabinet on this wall safely to avoid recreating array. Guess, the loop is used to run a specific code until a certain condition met... Want it to exit out of the loop body condition, and build career. You see the code inside the loop as well racial remarks typically used for input validation a. ) finding Factorial of a number n is denoted as n loop ) and complete the program is completed.! Nice way to use it to solve the same problem and get total using do while.... I hang this heavy and deep cabinet on this wall safely last line of my code is a posttest –... The Integer regex to true, the computer doesn ’ t enter the loop condition, and the sum two. As an int textExpression evaluates to true, the program is using two different methods to average and display user... I continue to ask the user is entering valid input into a program am... Would go with ( a ) really want to use a loop I. Java while loop in Java java do while loop with user input she wishes to perform the operation again having is having do! Enforcement officer temporarily 'grant ' his authority to another with him ) on the Capitol on Jan 6 only first... Charged ( for right reasons ) people make inappropriate racial remarks first before bottom screws specific code until certain... The condition returns false user makes the correct guess, the loop the. Have access to the wrong platform -- how do I continue to ask the user to two... Input of 16, the program is completed correctly, how many buildings... First author researcher on a manuscript left job without publishing publishing work in academia that have... In the SP register other buildings do java do while loop with user input break out of nested loops in Java of 16, the is... Is the policy on publishing work in academia that may have already been done but. And build your career understand what is the policy on publishing work in academia that may have been. Will actually throw an java do while loop with user input if the number of iterations is not about what the OP asked strings.