What is this error

#1

Exception in thread “main” java.lang.NumberFormatException: For input string: “”
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:592)
at Main.main(Main.java:10)

#2

@mishikasrvastava,

This is caused when you try to convert integer to string or vice-versa. Can you please share your code as well? I will be able to help you better

#3

import java.util.; public class Main { public static void main(String args[]) { Scanner sc = new Scanner(System.in); int N = sc.nextInt(); int j=0; int decimal=0; int i=1; while(i<=N){ String s = sc.nextLine(); //int j=1; while(N!=NULL) int a= s%10; decimal=decimal+aMath.pow(2,j); s=s/10; }System.out.println(s); } } }

#4

import java.util.*; public class Main { public static void main(String args[]) { Scanner sc = new Scanner(System.in); int N = sc.nextInt(); int i = 1; while(i<=N){ String s = sc.nextLine(); int decimal = Integer.parseInt(s,2); System.out.println(decimal); } } }

#5

@mishikasrvastava,
Your second approach is incorrect and we won’t be using that anywhere. It is suggested that you use your own method for conversion to decimal.

#6

@mishikasrvastava,
For first approach:

https://ide.codingblocks.com/s/298637 corrected code.

Errors:

  1. int decimal and int j will be declared inside the for loop because we want them to reset after every iteration.
  2. Take input of binary numbers are long/int. If using string for that, you need to subtract the ASCII value of ‘0’ from every char to get the digit.
  3. Also, while using int we don’t use null, we use 0.
  4. i++ inside the while loop. Your loop was going to infinity!
#7

thank you for th help