Chapter 5, Problem 5.1PE

(Count positive and negative numbers and compute the average of numbers) Write a program that reads an unspecified number of integers, determines how many positive and negative values have been read, and computes the total and average of the input values (not counting zeros). Your program ends with the input 0. Display the average as a floating-point number. Here are sample runs:

Enter an integer, the input ends if it is 0: 1 2 -1 3 0  

The number of positives is 3

The number of negatives is 1

The total is 5.0

The average is 1.25

Enter an integer, the input ends if it is 0: 0

No numbers are entered except 0

Program Plan Intro

Count positive and negative numbers and compute the average of numbers

Program Plan:

• Include the required import statement.
• Define the class
  • Define the main() method using public static main.
    • Declare and initialize the required variables.
    • Declare the input scanner.
    • Read an input from the user.
    • Using while loop, check whether the integer is “0” or not
      • Check whether the integer is greater than “0”.
        • If so, increment the positive counter.
      • Check whether the integer is less than “0”.
        • If so, increment the negative counter.
      • Calculate the sum of integers.
      • Read the next input.
    • Display the sum and average of integers.

Program Description Answer

The below program is used to count number of positives and number of negatives which are presented as inputs and finally calculate its sum and average as follows:

Explanation of Solution

Program:

//import statement

import java.util.Scanner;

//class Excersise_1

public class Excersise_1 {

// main function

public static void main(String[] args) {

// declare and initialize the required variables

int count_Positive = 0, count_Negative = 0;

int counter = 0, sum = 0, integer;

// declare the input scanner

Scanner in = new Scanner(System.in);

// print the instruction

System.out.print("Enter an integer, the input ends if it is 0: ");

// read the integer value from user

integer = in.nextInt();

// using while loop, check the integer

while (integer != 0) {

// check if it is positive

if (integer > 0)

/* if so, increment the positive counter */

count_Positive++;

// check if it is negative

else if (integer < 0)

/* if so, increment the negative counter */

count_Negative++;

// calculate the total of integer

sum += integer;

// increment the counter

counter++;

// Read the next integer

integer = in.nextInt();

}

// check the counter is 0

if (counter == 0)

// if so, no inputs are read

System.out.println("No numbers are entered except 0");

else {

// print the number of positive integers

System.out.println("The number of positives is " + count_Positive);

// print the number of negative integers

System.out.println("The number of negatives is " + count_Negative);

// print the sum

System.out.println("The total is " + sum);

// print the overall average

System.out.println("The average is " + sum * 1.0 / counter);

}

}

}

Sample Output

Enter an integer, the input ends if it is 0: 1

2

-1

3

0

The number of positives is 3

The number of negatives is 1

The total is 5

The average is 1.25