读取文件并在Java中打印最大和最小编号

Question

I need to print the maximum and the minimum number inside this file... i tried everything and i cant seem to make it work. I am a beginner please help

public class Banck {

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        System.out.println("Welcome to JEEEZBANK");

        final int NUM_TO_QUIT = -99;

        String userin ;
        int num;

        System.out.println("Enter a file ending with .txt");
        Scanner scan = new Scanner(System.in);
        userin = scan.nextLine();

        // create file
        PrintWriter file = new PrintWriter(userin);

        for(int i=1; i<5; i++){
            System.out.println("enter first number "+i +" or -99 to quit");
            num = scan.nextInt();
            if(num == NUM_TO_QUIT){
                System.out.println("bye");
                System.exit(0);
            }
            file.println(num);

        }
        file.close();
        // read file and print smallest and biggest number
        Scanner read = new Scanner(file);
        while(read.hasNext()){

            // add the numbers to the array 
            int[] numlist = {num};
            // print the biggest and smallest number inside the numlist array.
        }
    }
}

Answer 1

One way is to create two variables where one keeps track of the current lowest number and the other keeps track of the current highest. For every number in the file, compare if it is lower then the current lowest number, if so replace it or if it is higher then the current highest number (and if so replace it).

You could actually compare and look for the min and max numbers while the user is inputting them instead of having a separate loop, since I presume that they are the same numbers.

Answer 2

Don't keep a list. Use two variables to keep track of max & min.

int min = Integer.MAX_VALUE;

int max = 0;

if(num < min) min = num;

if(num > max) max = num;

Assuming num is the integer being read from the file in the loop above.