CODEWITHSUNDEEP
java
Monster
Monster

Reputation: 19

Positive and Negative numbers in String

I have to make a program that allows the user to enter integer numbers until he press '0'. The program has to print: 1)The total number of the entered numbers 2) The number of the positive ones 3) The average of the positive ones 4) The number of the negative ones 5) The sum of the negatives

So far, all I could do is make the "enter untill '0' is pressed" and find the number of the entered numbers, which is a lot for me and my programing skills. I am having troubles trying to find out if the number is positive or negative. Probably I am not comparing them right, so I would love if I get a little help from someone advanced.

Here's my code so far:

import java.io.*; 

class Nums { 
  public static void main(String args[])  
    throws IOException 
  { 
    BufferedReader br = new BufferedReader(new 
                            InputStreamReader(System.in)); 
    String str;
    int EnteredNumbers = -1;
    int Positive = 0;
    int Negative = 0;
    int NegativeSum = 0;
    double AveragePositive = 0;

    System.out.println("Enter '0' to quit."); 
    System.out.println("Enter Numbers: "); 
    do { 
      EnteredNumbers++;
      str = br.readLine();

    } while(!str.equals("0")); 
      System.out.println("You have have entered "+EnteredNumbers+ " numbers!");
      System.out.println("You have have entered "+Positive+ " Positive numbers!");
      System.out.println("The Average of the Positive Numebers is "+AveragePositive+ "!");
      System.out.println("You have have entered "+Negative+ " Negative numbers!");
      System.out.println("The Sum of the Negative numbers is "+NegativeSum+ "!");
  } 
}

Upvotes: 1

Views: 8701

Answers (7)

Okx
Okx

Reputation: 363

Change your do-while loop: it is using Strings, not integers:

do { 
      EnteredNumbers++;
      num = sc.nextInt();

    } while(num != 0);

Also, you need to import the scanner utility:

import java.util.Scanner;

Don't use a BufferedReader, but use:

static Scanner sc = new Scanner(System.in);

Also, you would want to use a checker for your positive and negative numbers inside your do-while loop:

if(Integer.parseInt(num)<0) { Negative++; }
else { Positive++; }

I've also added a try-catch statement to handle an error if someone doesn't enter an int:

      try {
      num = sc.nextInt();
      }
      catch(Exception e) {System.out.println("Invalid integer"); System.exit(0); }

I added a little bit of code that takes the 0 off when it prints the numbers, as I realise it will include 0 when you type it in to exit. Change your class statement to public, it's just programming:

public class Nums {

Also, I add a negative-number counter in the main code, and an averager. Here is the complete code, to avoid confusion:

import java.io.*; 
import java.util.Scanner;
public class prime { 
  static Scanner sc = new Scanner(System.in);
  public static void main(String args[])  
  { 
    int EnteredNumbers = 0;
    int Positive = 0;
    int Negative = 0;
    int NegativeSum = 0;
    double AveragePositive = 0;
    int num = 0;
    int PosTotal = 0;
    System.out.println("Enter '0' to quit."); 
    System.out.println("Enter Numbers: "); 
    do { 
      try {
      num = sc.nextInt();
      }
      catch(Exception e) {System.out.println("Invalid integer!"); System.exit(0); }
      if(num<0) { Negative++; NegativeSum += num; }
      if(num>0){ Positive++; PosTotal += num; }
      EnteredNumbers++;
    } while(num != 0); 
      AveragePositive = PosTotal / Positive;
      EnteredNumbers -= 1;
      System.out.println("You have have entered "+EnteredNumbers+ " numbers!");
      System.out.println("You have have entered "+Positive+ " Positive numbers!");
      System.out.println("The Average of the Positive Numbers is "+AveragePositive+ "!");
      System.out.println("You have have entered "+Negative+ " Negative numbers!");
      System.out.println("The Sum of the Negative numbers is "+NegativeSum+ "!");
  } 
}

Hope it helps! Note I have trial-tested it, and it works brilliantly. If you have any errors with this please tell me :)

Upvotes: 0

Bhargav Rao
Bhargav Rao

Reputation: 52181

Firstly as pointed out Integer.parseInt is used in java to convert from String to int. Secondly you need to have a extra variable to store and accumulate the total of positive numbers too. I have added a try-catch exception block to handle errors.

Here is a code for reference. 

import java.io.*; 

public class Nums { 
  public static void main(String args[])  
    throws IOException 
  { 
    BufferedReader br = new BufferedReader(new 
                            InputStreamReader(System.in)); 
    String str;
    int EnteredNumbers = -1;
    int Positive = 0;
    int Negative = 0;
    int NegativeSum = 0;
    int PositiveSum = 0; // Added extra variable
    double AveragePositive = 0;

    System.out.println("Enter '0' to quit."); 
    System.out.println("Enter Numbers: "); 
   try{
    do { 
      EnteredNumbers++;
      str = br.readLine();

    int num = Integer.parseInt(str);


    if (num>0)
      {
        Positive++;
        PositiveSum+=num;
      }
      else if (num<0)
      {
        Negative++;
        NegativeSum+=num;
      }
    } while(!str.equals("0")); 
    AveragePositive = (double)PositiveSum/(double)Positive;
      System.out.println("You have have entered "+EnteredNumbers+ " numbers!");
      System.out.println("You have have entered "+Positive+ " Positive numbers!");
      System.out.println("The Average of the Positive Numebers is "+AveragePositive+ "!");
      System.out.println("You have have entered "+Negative+ " Negative numbers!");
      System.out.println("The Sum of the Negative numbers is "+NegativeSum+ "!");
    }
    catch (java.lang.NumberFormatException e)
    {
        System.out.println("Wrong format");
    }  

} 
}

Output if there are no errors

Enter '0' to quit.
Enter Numbers: 
1
5
5
-5
-5
0
You have have entered 5 numbers!
You have have entered 3 Positive numbers!
The Average of the Positive Numebers is 3.6666666666666665!
You have have entered 2 Negative numbers!
The Sum of the Negative numbers is -10!

Upvotes: 2

Anakar
Anakar

Reputation: 112

Hope the below code achieves what you want to do

import java.io.*; 

class Nums { 
  public static void main(String args[])  
    throws IOException 
  { 
    BufferedReader br = new BufferedReader(new 
                            InputStreamReader(System.in)); 
    String str;
    int EnteredNumbers = -1;
    int Positive = 0;
    int Negative = 0;
    int NegativeSum = 0;
    double AveragePositive = 0;
    double PositiveSum = 0;

    System.out.println("Enter '0' to quit."); 
    System.out.println("Enter Numbers: "); 
    do { 
      EnteredNumbers++;
      str = br.readLine();
      if(Integer.parseInt(str) > 0){
          Positive++;
          PositiveSum = PositiveSum + Integer.parseInt(str);
          AveragePositive = PositiveSum/Positive;
      }
      if(Integer.parseInt(str) < 0){
          Negative++;
          NegativeSum = NegativeSum + Integer.parseInt(str);
      }

    } while(!str.equals("0")); 
      System.out.println("You have have entered "+EnteredNumbers+ " numbers!");
      System.out.println("You have have entered "+Positive+ " Positive numbers!");
      System.out.println("The Average of the Positive Numebers is "+AveragePositive+ "!");
      System.out.println("You have have entered "+Negative+ " Negative numbers!");
      System.out.println("The Sum of the Negative numbers is "+NegativeSum+ "!");
  } 
}

Upvotes: 1

James Fox
James Fox

Reputation: 691

I have added an extra variable called PositiveSum to assist with the AveragePositive calculation.

In order to perform this calculation, you need to ensure the value is an Integer so I have added the parse statement.

class Nums { 
  public static void main(String args[])  
    throws IOException 
  { 
    BufferedReader br = new BufferedReader(new 
                        InputStreamReader(System.in)); 
    String str;
    int EnteredNumbers = -1;
    int Positive = 0;
    int Negative = 0;
    int NegativeSum = 0;
    int PositiveSum = 0; 
    double AveragePositive = 0;

    System.out.println("Enter '0' to quit."); 
    System.out.println("Enter Numbers: "); 
    do { 
      EnteredNumbers++;
      str = br.readLine();
      int number = Integer.parseInt(str);
      if(number<0) {
          Negative++;
          NegativeSum += number;
      } else if(number>0) {
          Positive++;
          PositiveSum += number;

      }

    } while(!str.equals("0"));
      AveragePositive = PositiveSum / EnteredNumbers;
      System.out.println("You have have entered "+EnteredNumbers+ " numbers!");
      System.out.println("You have have entered "+Positive+ " Positive numbers!");
      System.out.println("The Average of the Positive Numebers is "+AveragePositive+ "!");
      System.out.println("You have have entered "+Negative+ " Negative numbers!");
      System.out.println("The Sum of the Negative numbers is "+NegativeSum+ "!");
  } 
}

Upvotes: 0

Bruce
Bruce

Reputation: 8879

check by parsing String to int 

Integer.parseInt(str)>0  //positive number
Integer.parseInt(str)<0 //negative



do { 
      EnteredNumbers++;
      str = br.readLine();
      int number= Integer.parseInt(str);
      if(number>0){  //do positive stuffs}
      else if(number<0){//do negative stuffs}
    } while(!str.equals("0"));

Upvotes: 1

Tur1ng
Tur1ng

Reputation: 834

Try using Integer.parseInt() to get an int from your string str, and checking to see if the integer is < 0 (negative) or > 0 (positive)

Upvotes: 0

SMA
SMA

Reputation: 37093

Create a list and keep adding the numbers into List. You should do something like:

List<Integer> numberList = new ArrayList<Integer>();

do { 
  str = br.readLine();
  int number = Integer.parseInt(str);
} while(number != 0);

And then use for loop to do count like:

int negativeNumberSum = 0;
int positiveNumberSum = 0;
int positiveNumberCounts = 0;
for (int i =0; i<numberList.size(); i++) {
    if (numberList.get(i) >= 0) {
        positiveNumberSum += numberList.get(i);
        positiveNumberCounts ++;
    } else {
        negativeNumberSum += numberList.get(i);
    }
}

//print average of positive as positiveNumberSum /(double) positiveNumberCounts if positiveNumberCounts != 0
//print average of positive as negativeNumberSum / (double)(numberList.size() - positiveNumberCounts) same if (numberList.size() - positiveNumberCounts) != 0
//print positive count as positiveNumberSum  and same for negative.
//

Upvotes: 0

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