StringTokenizer数组

Question

Java. So I want to input an array of integers and then print out the max value using StringTokenizer. I know how to do this using integers, but when I try to do it with an array the String to int command (Integer.parseInt) fails me - cannot convert from int to int[].

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

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String strTmp;
        StringTokenizer strTok;
        while ((strTmp = in.readLine()) != null && strTmp.length() != 0) {
            strTok = new StringTokenizer(strTmp);

        int[] c;

        c = Integer.parseInt(strTok.nextToken());

        int max = 0;
        for (int i = 0; i < c.length; i++) {
            if (c[i] > max) {
                max = c[i];
            }
        }
        System.out.println(max);
    }
}
}

How do I go about solving this or are there other commands I should be using?

Answer 1

You seem to be confused about whether you actually want an array or not. You're parsing a single value , but trying to assign that int to c which is an array variable. You don't really need one, as you only need to remember the current maximum, and the value you've just parsed:

int max = Integer.MIN_VALUE;
while (strTok.hasMoreTokens()) {
    int value = Integer.parseInt(strTok.nextToken());
    if (value > max) {
        max = value;
    }
}

If you really want an array, then you'll need to know how many tokens there are before you parse them, which is tricky.

Another alternative would be to create a List<Integer> :

// First parse everything...
List<Integer> values = new ArrayList<>();
while (strTok.hasMoreTokens()) {
    values.add(Integer.parse(strTok.nextToken());
}

// Then you can find the maximum value in the list

Personally I prefer the first approach, if you only need to find the maximum value.

Answer 2

 int[] c;

 c = Integer.parseInt(strTok.nextToken());

You are trying to assign a single Integer object to an array of int .

Rather, use int[index] = Integer.parseInt(strTok.nextToken());

Answer 3

Integer.parseInt(String) returns an integer, not an Integer array . You have to store the return value Integer in an int variable like

int i = Integer.parseInt(String);

You have to iterate the integer array and set it's index value to the returned integer value

for (int i = 0; i < c.length; i++) {
           c[i] = Integer.parseInt(strTok.nextToken());
            if (c[i] > max) {
                max = c[i];
            }
        }

Hope this helps!