CODEWITHSUNDEEP
javavalidation
Jessica Rush
Jessica Rush

Reputation: 25

How do you get your program to repeat if input is invalid instead of continuing with invalid input?

I am trying to validate a user input, cuPerTerm > 12

I get the error message but the program continues and uses the invalid input to run 

package gradplanner;

import java.util.Scanner;

public class GradPlanner {

int cuToComp;
int cuPerTerm;

public static void main(String[] args) {

    final double COST = 2890.00; //flat-rate tuition rate charged per term
    final int MONPERTERM = 6; //number of months per term
    int cuToCompTotal = 0;   
    int numTerm;
    int numMonToComp;
    double tuition;



      //prompt for user to input the number of CUs for each individual course remaining.
    Scanner in = new Scanner(System.in);
    System.out.print("Please enter the number of CUs for each individual course you have remaining, Entering a - number when finished. ");     
    int cuToComp = in.nextInt();



      //add all CUs from individual courses to find the Total number of CUs left to complete.
    while (cuToComp > 0)
    {
      cuToCompTotal += cuToComp;

      System.out.print("Please enter the number of CUs for each individual course you have remaining, Entering a - number when finished. ");
      cuToComp = in.nextInt();
    }

    System.out.println("The total number of CUs left is " + cuToCompTotal);



      //prompt for user to input how many CUs they plan to take per term.
    System.out.print("How many credit units do you intend to take per term? ");
    int cuPerTerm = in.nextInt();

        if (cuPerTerm <12) //validate input - Undergraduate Students Must enroll in a minimum of 12 CUs per term
        {
            System.out.print("Undergraduate Students must enroll in a Minimum of 12 CUs per Term. ");

        }


        //Calculate the number of terms remaining, if a remain is present increase number of terms by 1.   
     numTerm = cuToCompTotal/cuPerTerm;
        if (cuToCompTotal%cuPerTerm > 0)
        {
          numTerm = numTerm + 1;  
        }
     System.out.println("The Number of Terms you have left is " + numTerm + " Terms. ");



       //Calculate the number of Months left to complete
     numMonToComp = numTerm * MONPERTERM;
     System.out.println("Which is " + numMonToComp + " Months. ");



       //calculate the tuition cost based on the number of terms left to complete.
     tuition = numTerm * COST;
     System.out.println("Your Total Tuition Cost is: " + "$" + tuition +" . ");

}
}

I need it to continue to re-ask until 12 or something greater is entered. and then continue the program.

Upvotes: 0

Views: 2199

Answers (5)

dognose
dognose

Reputation: 20889

There are pitfalls: Simple doing scanner.nextInt() will give you the next Integer of the CURRENT Line.

If the user types in test, nextInt() will throw an InputMismatchException, you have to handle. Also the int will NOT be consumed

So you have to call scanner.nextLine() in between to Clean the current (mismatched) result.

All together something like this:

do{
    try
       {
       System.out.print("Enter number > 12: ");
       System.out.flush();
       number = scanner.nextInt(); 
       if (number > 12)
         done = true;
     }
     catch(InputMismatchException e) {
       System.out.println("This is not a number");
       scanner.nextLine() //!Important!
     }
   }while(!done);

Upvotes: 1

alterfox
alterfox

Reputation: 1695

I think that a do-while loop will best suit your needs:

    int val;
    do {
        val = in.nextInt();
    } while (val < 12);

Upvotes: 0

Prateek
Prateek

Reputation: 1926

Add this to continue getting input till it satisfies your condition:

while(cuPerTerm <= 12){
//Ask use to provide input
}

It is simple while loop which checks your input condition and continues taking input till it is satisfied.

Edit: - Initialize your cuPerTerm =0

 while(cuPerTerm <= 12)
    {
        System.out.print("Please enter the number of CUs for each individual course you have remaining, Entering a - number when finished. ");     
        int cuToComp = in.nextInt();
    }

Upvotes: 1

Miserable Variable
Miserable Variable

Reputation: 28752

Here's a simple solution:

int cuPerTerm = -1; // intialize to an invalid value
while (cuPerTerm < 12) {
    System.out.print("How many credit units do you intend to take per term? ");
    int cuPerTerm = in.nextInt();

    if (cuPerTerm <12) { //validate input - Undergraduate Students Must enroll in a minimum of 12 CUs per term

        System.out.print("Undergraduate Students must enroll in a Minimum of 12 CUs per Term. ");
    }
}

Upvotes: 1

rgettman
rgettman

Reputation: 178263

You should use a while loop so that you continue looping until cuPerTerm is at least 12. Remember to take the user input again with cuPerTerm = in.nextInt(); inside the while loop.

Upvotes: 1

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