If the instruction to exit the program

Question

Suppose you have a binary file containing numbers whose type is either int or double. You do not know the order of the numbers in the file, but their order is written to the line at the beginning of the file. The string consists of the letters i for int and d for double, in the order of the types of subsequent numbers. A string is written using the writeUTF method.

For example, the line "iddiiddd" indicated that the file contains eight values, namely: one integer followed by two doubles, and then two integers followed by three doubles.

My problem is that if there are more letters than numbers in a line, how can I create an if statement telling the user that there is an error in the file they are trying to read?

I tried using this where "count" is the number of numbers and "length" is the length of the string, but that did not work.

    if(count!=length){
        System.out.println("Error in file: Length of string and numbers are not equal");
        System.exit(0);
    }

the rest of my code is this:

public static void main(String[] args) {

    Scanner keyboard=new Scanner(System.in);
    System.out.print("Input file: ");
    String fileName=keyboard.next();
    int int_num_check=0;
    double double_num_check=9999999999999999999999999999.999999999;
    int int_num=0;
    double double_num=0.0;
    int count=0;

    try{
        FileInputStream fi=new FileInputStream(fileName);
        ObjectInputStream input=new ObjectInputStream(fi);

        String word=input.readUTF();
        int length=word.length();

        for(int i=0;i<length;i++){

            if(word.charAt(i)=='i'){
                int_num=input.readInt();
                System.out.println(int_num);
                if(int_num>int_num_check){
                    int_num_check=int_num;
                }
            }

            else if(word.charAt(i)=='d'){
                double_num=input.readDouble();
                System.out.println(double_num);
                if(double_num<double_num_check){
                    double_num_check=double_num;
                }
            }

            else{
                System.out.println("Error");
                System.exit(0);
            }
            count++;

        }

        System.out.println("count: "+count);
        System.out.println("length "+length);

        if(count!=length){
            System.out.println("Error in file: Length of string and numbers are not equal");
            System.exit(0);
        }

         String checker=input.readUTF();
            if(!checker.equals(null)){
                System.out.println("Error");
                System.exit(0);
            }

        input.close();
        fi.close(); 

}
    catch(FileNotFoundException e){
        System.out.println("Error");
        System.exit(0);
    }
    catch(EOFException e){

        System.out.println("Largest integer: "+int_num_check);
        System.out.println("Smallest double: "+double_num_check);
        System.exit(0);
    }
    catch(IOException e){
        System.out.println("Error");
        System.exit(0);
        }


}

}

Answer 1

If there are more letters than numbers, you probably reached the end of the file (eof). Check eof after each file reads the number and reports an error if you get to the point where all expected numbers have been read.

Answer 2

I think that maybe the problem is how your file was created. Try creating it using this code:

try {
    ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("C:/temp/file.txt"));
    oos.writeUTF("idid");
    oos.writeInt(8);
    oos.writeDouble(4.33316);
    oos.writeInt(2);
    oos.flush();
    oos.close();
} catch (Exception ex) {
    ex.printStackTrace();
}

Then read it using your code, it should throw an EOFException.

Answer 3

, /, EOFException, EOF, - / .

Since the EOF exception should only increase when you have more letters than numbers (since you do your readings based on length word), you have to move inward to catch your

System.out.println("Error in file: Length of string and numbers are not equal");
System.exit(0);