CODEWITHSUNDEEP
javabluej
Dhruv
Dhruv

Reputation: 37

Ask for input again if wrong input is entered

I am new to Java programming. I want the program to ask for input again if wrong input is entered by the user. What must I do? Please help! Jump to the 'if else if' part if you want to avoid the mess... And not being rude but please don't request for closing the question if you can't answer.

case 'A': case 'a':
            System.out.println("You selected NOS Tank.");
            int price;
            double quantity;
            double variant=0; 
            System.out.println("Select the variant: ");                                                    
            System.out.println("Enter 'D' without apostrophe for dry or 'W' for wet");
            variant=xss.next().charAt(0);                                                                  
            if (variant=='D' || variant=='d')
            {
                System.out.println("The price of dry nitrous oxide system is: $600");
            }
            else if (variant=='w' || variant=='W')
            {
                System.out.println("The price of wet nitrous oxide is: $740");
            }
            else 
            {
                System.out.println("Invalid input.");                                                      
            }

Upvotes: 0

Views: 4293

Answers (1)

TechIntelTan
TechIntelTan

Reputation: 26

It has been 28 days since you asked your doubt so I don't know if you have come across the answer or not but here's my solution. To accept the correct input you need to make use of a while loop, loops are iterations in java which run for multiple number of times as per the given instructions. In this program I have incorporated a while loop whose condition is true always, so basically it is an infinite loop. If the inputted variant is correct and matches with any one of the if condition then the loop will break automatically because of the "break;" statement. break; is a jump statement in java which allows you to terminate a loop when your requirements are met. Given below is your required program code. Hope this solves you query :)

case 'A': case 'a':
    System.out.println("You selected NOS Tank.");
    int price;
    double quantity;
    double variant=0; 
    System.out.println("Select the variant: ");
    
    while(true)
    {                                                    
        System.out.println("Enter 'D' without apostrophe for dry or 'W' for wet");
        variant=xss.next().charAt(0);                                                                  
        if (variant=='D' || variant=='d')
        {
            System.out.println("The price of dry nitrous oxide system is: $600");
            break;
        }
        else if (variant=='w' || variant=='W')
        {
            System.out.println("The price of wet nitrous oxide is: $740");
            break;
        }
        else 
        {
            System.out.println("Invalid input.");     
            System.out.println("Please enter the variant again:");                                                
        }
    }

Upvotes: 1

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