CODEWITHSUNDEEP
javacloud9-ide
newcode
newcode

Reputation: 63

I need help to write a code that finds the largest difference between two integers in a sequence

I need to write a code that finds the largest difference between two integers in a sequence. The user is supposed to input the stock prices from 10 consecutive days and the program will tell you the biggest day to day change. I'm stuck though.

import java.util.Scanner;

public class Change {

 public static void main (String [] args) {
    final int days = 10;
     int largeDiff = 0; // largest difference
 Scanner sc = new Scanner(System.in);
 System.out.println("Enter a stock price:");

int price1 = sc.nextInt();

 int price2 = sc.nextInt();

 int diff1 = price1 - price2;

 for (int i = 1; i <= 8; i++) {
    int priceA = sc.nextInt();
    int priceB = sc.nextInt();

    int diff2 = priceA - priceB;

    if (diff2 > diff1) {
        diff2 = largeDiff;
    }
    else {
        diff2 = diff1;
    }

 }

 System.out.println(largeDiff);

}

}

Upvotes: 1

Views: 71

Answers (4)

Codex
Codex

Reputation: 3

import java.util.Scanner;
public class Change {

public static void main (String [] args) {
final int days = 10;
int largeDiff = 0; // largest difference
int diff1 = 0;
Scanner sc = new Scanner(System.in);
System.out.println("Enter a stock price:");

for (int i = 0; i < 5; i++) {
int priceA = sc.nextInt();
int priceB = sc.nextInt();

int diff2 = Math.abs(priceA - priceB);

if (diff2 > diff1) {
    largeDiff = diff2;
    diff1 = diff2;

}
}
System.out.println(largeDiff);

}
}

Upvotes: 0

Shababb Karim
Shababb Karim

Reputation: 3733

I for one like to take inputs first and then do all the necessary calculations. Also you are supposed to take 10 inputs from the user right? So taking a loop which moves around 8 times and each time takes 2 inputs from the Scanner basically means you need to provide a total of 16 inputs, which is definitely not what you want. My solution is given below for reference. 

public class Change
{
    public static void main (String[] args)
    {
        Scanner sc = new Scanner(System.in);

        int totalDays = 10;
        int stockPrices[] = new int[totalDays];

        for(int c = 1; c <= totalDays; c++) {

            System.out.printf("Enter stock price for day %d\n", c);
            stockPrices[c - 1] = sc.nextInt();
        }

        int largestDiff = -1;
        for(int c = 0; c < totalDays - 1; c++) {

            int diff = Math.abs(stockPrices[c] - stockPrices[c + 1]);
            if(diff > largestDiff) {

                largestDiff = diff;
            }
        }

        System.out.printf("Largest difference in stock price is %d\n", largestDiff);
    }
}

Upvotes: 0

D.B.
D.B.

Reputation: 4713

The user is supposed to input the stock prices from 10 consecutive days and the program will tell you the biggest day to day change

Your code is allowing the user to enter more than 10 prices. You should be tracking the difference in price as the user enters the next price. See the below algorithm: 

import java.util.Scanner;

public class LargestDiff {

    public static void main(String[] args) {
        final int days = 10;
        Scanner sc = new Scanner(System.in);

        int largeDiff = calculateLargestDiff(sc, days);

        System.out.println(largeDiff);
        sc.close(); //don't forget to close scanner
    }

    public static int calculateLargestDiff(Scanner sc, int days){
        int largeDiff = 0;
        System.out.println("Enter a stock price for day 1");

        int price1 = sc.nextInt();

        for (int i = 2; i <= days; i++) {
            System.out.println("Enter a stock price for day "+i);
            int price2 = sc.nextInt();

            int diff2 = Math.abs(price1 - price2);
            price1 = price2;

            if (diff2 > largeDiff) {
                largeDiff = diff2;
            }
        }
        return largeDiff;
    }
}

You may notice I created a second method that takes its dependencies - a Scanner and an int as parameters. This makes it easier to write automated tests.

Something else to consider - your code doesn't handle invalid inputs. For example if the user enters a letter instead of an integer. You should probably add logic to handle these kinds of scenarios.

Upvotes: 1

Shubhendu Pramanik
Shubhendu Pramanik

Reputation: 2751

You are assigning largeDiff to diff2. Modify your code like below:

if (diff2 > diff1) {
        largeDiff = diff2;
    }
    else {
        largeDiff = diff1;
    }

Also your code have some problem. To find largest difference:

EDIT: Do below modifications:

public static void main(String[] args) {
    final int days = 10;
    int largeDiff = 0; // largest difference
    Scanner sc = new Scanner(System.in);
    System.out.println("Enter a stock price:");

    int price1 = sc.nextInt();

    int price2 = sc.nextInt();

    int diff1 = price1 - price2;
    largeDiff = Math.abs(diff1);

    for (int i = 1; i <= 8; i++) {
        int priceA = sc.nextInt();
        int priceB = sc.nextInt();

        int diff2 = Math.abs(priceA - priceB);

        if (diff2 > largeDiff) {
            largeDiff = diff2;
        }
    }

    System.out.println(largeDiff);

}

N.B: Math::abs is used to find absolute value

Upvotes: 2

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