Java - For Loop will not complete, crashes after only three cycles

Question

this is part of some coursework which I would rather figure out for myself so if possible could you please not give the answer right out but point me in the right direction or tell me where my error is.

I have to create some code that will read text from a file and then do some other things with it, my problem is after reading the third block of text my for loop fails.

here is the text i have to read

Unit One
4
32 8
38 6
38 6
16 7

Unit Two
0

Unit Three
2
36 7
36 7

Unit Four
6
32 6.5
32 6.5
36 6.5
36 6.5
38 6.5
38 6.5

Unit Five
4
32 6.5
32 8
32 7
32 8

...

This goes up to unit 9

it is a .txt file in the same directory as my code. here is my code.

import java.io.*;
import java.util.*;
import javax.swing.JOptionPane;
import java.util.*
;
public class stringvariable {

public static void main(String[] args) throws FileNotFoundException
{
    String shop; //shop unit
    int num; // number of sales assistants
    int num2 = 9; // number of units
    int hour; //hours worked
    int rate; // rate of pay
    int total = 0; // total cost
    int i = 0;
    int sum;

Scanner inFile = new Scanner (new FileReader ("4001Comp-CW1-TASK3-Infile.txt")); //opens the CW1-task3-Infile file          

for (int b = 0; b <num2; b++)// for loop to read through all 9 shop units
{
    shop = inFile.nextLine();
    num = inFile.nextInt();

        for (i = 0; i <num; i++)// for loop repeats as many times as there     are     staff.
        {hour = inFile.nextInt();
        rate = inFile.nextInt();

        total += (rate*hour);
        System.out.println(total);}

    System.out.println(shop +"s total cost is  "+ total);

    shop = inFile.nextLine();
    shop = inFile.nextLine();
    num = 0;
    hour= 0;
    rate = 0;
    total = 0;   }


}
}

my printouts are exactly what I need up until 'unit 4'

256
484
712
824
Unit Ones total cost is  824


Unit Twos total cost is  0


252
504
Unit Threes total cost is  504


Exception in thread "main" java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:909)
    at java.util.Scanner.next(Scanner.java:1530)
    at java.util.Scanner.nextInt(Scanner.java:2160)
    at java.util.Scanner.nextInt(Scanner.java:2119)
    at stringvariable.main(stringvariable.java:28)

Answer 1

Unit 4 seems to contain floating point numbers, which you are reading with nextInt(), hence the exception .

You can use the hasNextInt() and hasNextDouble() methods to handle this gracefully :)