java.lang.NumberFormatException using parseInt

Question

I'm trying to take a digit from a string and perform operations on it. This is the relevant code I'm working on (updated):

    String cardNumber;
    String curNum;
    long currentNum;
    int firstNum;
    int randNum;
    int i;
    long sum = 0; 

 while (i <= 15) {
            //Delete this line if it doesnt work
            currentNum = Long.parseLong(cardNumber.substring(i));
        if (i % 2 == 0) {
            //currentNum = Integer.parseInt(cardNumber.charAt(i));
            currentNum = currentNum * 2;
            if (currentNum > 9) {
                currentNum = currentNum - 9;
                sum = sum + currentNum;
            }
            else {
                //currentNum = Integer.parseInt(cardNumber.charAt(i));  
                sum = sum + currentNum;
            }   
            i++;
        }
        long lastVal = 10 - (sum % 10);
        char charNum = (char) lastVal;
        //add int to char statement here
        cardNumber = cardNumber + charNum;
    }
        System.out.println(cardNumber);

        userNum--;
    }

The // code is another option I was working on and didn't want to lose, so if there's a way to make it work using that, that's great! The error message this code returns is:

Exception in thread "main" java.lang.NumberFormatException: For input string: "64406849400888" at java.base/java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) at java.base/java.lang.Long.parseLong(Long.java:692) at java.base/java.lang.Long.parseLong(Long.java:817) at MasterCardGenerator.main(MasterCardGenerator.java:54)

@hev1 but he uses it: currentNum = parseInt(....); and later sum = sum + currentNum; (but I admit it is confusing because of the line break before parseInt) — Thomas Kläger
– Thomas Kläger, Commented Jul 9, 2020 at 5:59

Kevin Anderson · Accepted Answer · 2020-07-09 06:21:16Z

2

You said you're trying to take "a" digit from a string. If that's truly the case, and you are trying to examine cardNumber one digit at a time, then you want cardNumber.substring(i, i+1) instead of cardNumber.substring(i).

Read the javadocs for substring(int) and substring(int, int) to understand why.

edited Jul 9, 2020 at 6:21

answered Jul 9, 2020 at 6:15

Kevin Anderson

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Comments

Severin Nitsche · Accepted Answer · 2020-07-09 08:32:34Z

1

The problem is that the domain of integers is between [-2^31,2^31[, indeed between [-2,147,483,648 to +2,147,483,647]. A possible solution is to parse the string using Long.parseLong(arg)

public class Test{

     public static void main(String []args){
         System.out.println("Integer.MAX_VALUE: " + Integer.MAX_VALUE);
         System.out.println("Long.MAX_VALUE: " + Long.MAX_VALUE);
         Long var = Long.parseLong("267574698286122");
         System.out.println("Printing content of 'var': " + var);
     }
}

And the output is:

Integer.MAX_VALUE: 2147483647
Long.MAX_VALUE: 9223372036854775807
Printing content of 'var': 267574698286122

edited Jul 9, 2020 at 8:32

Severin Nitsche

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answered Jul 9, 2020 at 6:17

Idriss Riouak

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Comments

cse · Accepted Answer · 2020-07-12 08:25:17Z

1

The problem is that the range string you are trying to format is larger than range of int.

To solve this problem, you need to change the line Integer.parseInt(cardNumber.substring(i)); with Long.parseLong(cardNumber.substring(i));.

See the range off different data types here. Also you can see, for int see here the Integer.MIN_VALUE and Integer.MAX_VALUE and for long see here the Long.MIN_VALUE and Long.MAX_VALUE

UPDATED

As per updated question, String passed is 64406849400888 so valid index for i are 0 <= i <= 13. Apart from that above code looks fine. 64406849400888 can be parsed in long. See it the parsing here

edited Jul 12, 2020 at 8:25

answered Jul 9, 2020 at 6:02

cse

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6 Comments

Jenna Crist Over a year ago

Hi! I just tried that and I'm getting a similar error message! Just to make sure, the code was supposed to look like this, correct?

while (i <= 15) { 				currentNum = Long.parseLong(cardNumber.substring(i)); 			if (i % 2 == 0) { 				//currentNum = Integer.parseInt(cardNumber.charAt(i)); 				currentNum = currentNum * 2; 				if (currentNum > 9) { 					currentNum = currentNum - 9; 					sum = sum + currentNum; 				} 				else { 					//currentNum = Integer.parseInt(cardNumber.charAt(i));	 					sum = sum + currentNum; 				}	 				i++; 			}

.

Jenna Crist Over a year ago

Sorry about the formatting on the previous comment, it wouldn't let me fix anything.

cse Over a year ago

@JennaCrist What is the type of currentNum and sum. It should also be long.

Jenna Crist Over a year ago

They're both long type!

cse Over a year ago

@JennaCrist Can you add here updated code and exception log?

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