2

So I'm trying to read all the input from one line, using scanner, then take the values and find the second largest. I would use an array BUT I am not allowed. You are supposed to enter 10 integers, hit enter and evaluate them.

Something like this:

10 20 30 40 50 60 70 80 90 100 ENTER

Second highest number is: 90

I can't manage to solve it at all. It should be easy but I have no idea.

public class SecondLargest {

public static void main(String[] args) {
    {
        int largest = 0;
        int secondLargest = 0;
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter integers: ");
        int numbers = sc.nextInt();
        largest = numbers;

        while (sc.hasNextInt()) {
            if (numbers > largest) {
                secondLargest = largest;
                largest = numbers;
            } else if (numbers > secondLargest) {
                secondLargest = numbers;
            }
        }
        System.out.println("Second largest number is: " + secondLargest);
        sc.close();

    }
}
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2
  • Do you mean you enter all 10 integers first and then press Enter? Or do you enter the first number, press Enter, second Number, press Enter, and so on? Commented Dec 7, 2019 at 9:50
  • 10 in a row. Edited my post for better clarification. Commented Dec 7, 2019 at 9:52

5 Answers 5

Reset to default
1

Start with assigning the first scanned integer to largest and secondLargest variables and then process the remaining nine integers in a loop as follows:

num = sc.nextInt();
if (num > largest) {
    secondLargest = largest;
    largest = num;
}

Demo:

import java.util.Scanner;

public class SecondLargest {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter 10 integers separated by single spaces: ");

        // Scan the first integer and assign it to largest and secondLargest
        int num = sc.nextInt();
        int largest = num;
        int secondLargest = largest;

        // Input 9 more integers
        for (int i = 1; i < 10; i++) {
            num = sc.nextInt();
            if (num > largest) {
                secondLargest = largest;
                largest = num;
            }
        }

        System.out.println("The second largest number is: " + secondLargest);
    }
}

A sample run:

Enter 10 integers separated by single spaces: 10 23 4 12 80 45 78 90 105 7
The second largest number is: 90

Note: This is just a sample program assuming that the input is in the correct format. I leave it to you to work on how to deal with the wrong input. It will be a good exercise for you.

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Comments

1 
/*
**In this code I've used BufferedReader class which is faster than Scanner 
Class as well as have large buffer of 8KB while Scanner has only 1KB.**
*/
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
public class Second_Highest {
 public static void main(String[] args) throws IOException
 {
    BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
    String[] s=br.readLine().split(" ");
    int a[]=new int[10];
    int max=Integer.parseInt(s[0]);
    for(int i=0;i<10;i++)
    {
        a[i]=Integer.parseInt(s[i]);
        if(a[i]>max)
        {
            max=a[i];
        }
    }
    int secondmax=Integer.parseInt(s[0]);
    for(int i=0;i<10;i++)
    {
        if(a[i]>secondmax && a[i]<max)
        {
            secondmax=a[i];
        }
    }
    System.out.print(secondmax);
 }   
}
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1 Comment

You do not need an array to solve this problem.
1

To read single line input, You can do this simply by eating the (\n) which is new line in Java.

Input : 1 2 3

\\Create the object of Scanner Class
Scanner sc = new Scanner(System.in);

int a = sc.nextInt();
int b = sc.nextInt();
int c = sc.nextInt();

// this will eat the new line and move forward for other inputs.
sc.nextLine()

To read in a loop or to store at 2D array.

Input : 1 2 3 3 4 5 6 7 8

//... do the above declaration of array

for ( int i = 0; i < n; i++){
   for( int j = 0; j < m; j++){
      arr[i][j] = sc.nextInt()
    } 
   sc.nextLine(); // you need to eat the \n here. 
}

This will work perfectly.

Now you should be able to get the input easily in a single line.

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1 Comment

You do not need an array to solve this problem.
0

Below snippet can be used to take multiple Integer Input on same line.

Scanner sc= new Scanner(System.in);    // Declare and Initialize Scanner
while(sc.hasNext())                    // While the input has data execute
    System.out.println(sc.nextInt());  // nextInt() method is used to take Integer data

For Multiple String input on same line separated by white space or a comma, we can use the following snippet

Scanner sc = new Scanner(System.in).useDelimiter("[,\\s+]");
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1 Comment

The issue for me here is that it takes nextInt, so it never really prints the first int.
0 
import java.util.*;
public class m1{
public static void main(String args[]){
Scannerscan = new Scanner(System.in);
Stringnum = scan.nextLine();
String[] strs = num.split("\\s+");
int[] arrs = new int[strs.length];
for(inti=0;i<strs.length;i++)
{
String stringnum = strs[i];
arrs[i] = Integer.parseInt(stringnum);
if(arrs[i]%2==0){
System.out.print(" ");
}
else{
System.out.print(arrs[i]);
}
}
scan.close();
}
}
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1 Comment

This is a program of a prime no. in which the input and out will in single line for multiple inputs taken by user. input :1 2 3 4 5 output 1 3 5

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