Error while trying to use Integer.parseInt(next_split[0]);

Question

The error is near a=Integer.parseInt(next_split[0]); What is happening? Why the error?

error:Exception in thread "main" java.lang.NumberFormatException: For input string:
    at java.lang.NumberFormatException.forInputString(Unknown Source)
    at java.lang.Integer.parseInt(Unknown Source)
    at java.lang.Integer.parseInt(Unknown Source)
    at JavaLoops.main(JavaLoops.java:(line_number_in_my_code)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

public class JavaLoops {

public static void main(String[] args) throws Exception {

    int t,a,b,n;


    Scanner in = new Scanner(System.in);
    t= in.nextInt();

    for(int i=0;i<t;i++)
    {
        String input=in.nextLine();
        String[] next_split = input.split(" ");
        System.out.println(next_split[0]);

        a=Integer.parseInt(next_split[0]);
        b=Integer.parseInt(next_split[1]);
        n=Integer.parseInt(next_split[2]);

        calculate(a,b,n);

    }
}
static void calculate(int a,int b,int n)
{
    int constant=a+((int) Math.pow(2,0)*b);
    System.out.print(constant+" ");
    int res=0;

    for(int i=1;i<n;i++)
    {
        res=constant+((int) Math.pow(2,i)*b);
        constant=res;
        System.out.print(res+" ");
    }

}   
}

Answer 1

This is because the position of scanner after in.nextInt(); will be just after your input integer.

in.nextLine(); inside the loop will then read nothing.

Solution either

1) Make the position for scanner to next new line

t= Integer.parseInt(in.nextLine());

2) Have a new Scanner Object

Scanner in2 = new Scanner(System.in);
String input=in2.nextLine();