Question
Write a program that calculates the average of N integers. The program should prompt the user to enter the value for N and then afterward must enter all N numbers. If the user enters a nonpositive value for N, then an exception should be thrown (and caught) with the message “N must be positive.” If there is any exception as the user is entering the N numbers, an error message should be displayed, and the user prompted to enter the number again.
Answer
import java.util.Scanner;
import java.util.InputMismatchException;
public class TestDemo
{
public static void main(String args[])
{
double total = 0, N, userInput;
Scanner input = new Scanner(System.in);
while (true)
{
System.out.print("Enter how many numbers(N) to calculate average:");
userInput = input.nextDouble();
if (userInput > 0)
{
N = userInput;
break;
}
else
System.out.println("N must be positive.");
}
for (int i = 0; i < N; i++)
{
while (true)
{
System.out.print("Enter number:");
try
{
userInput = input.nextDouble();
total += userInput;
break;
}
catch (InputMismatchException e)
{
input.nextLine();
System.out.println("Input must bea number. Try again");
}
}
}
System.out.println("Average: "+ total / N);
}
}
OUTPUT:
Enter how many numbers(N) to calculate average:-10
N must be positive.
Enter how many numbers(N) to calculate average:6
Enter number:10
Enter number:20
Enter number:40
Enter number:50
Enter number:200
Enter number:60
Average: 63.333333333333336
Discussions
derrickkorku
You could also use this solution:
package ExceptionHandling;
import java.util.InputMismatchException;
import java.util.Scanner;
public class Problem1 {
public static void averageOfNNumbers() throws InputMismatchException {
Scanner sc = new Scanner(System.in);
System.out.println("Please enter how many numbers to calculate average of:");
int num = sc.nextInt();
double total = 0;
if (num < 0) {
sc.close();
throw new InputMismatchException("Nonpositive number provided.");
}
for (int i = 0; i < num; i++) {
System.out.println("Enter number: ");
try {
double n = sc.nextDouble();
total += n;
}catch(Exception ex) {
System.out.println(ex.getMessage());
i--;
}
}
sc.close();
double average = total / num;
System.out.println("The average of the " + num + " numbers entered is " + average);
}
public static void main(String[] args) {
try {
averageOfNNumbers();
}catch(InputMismatchException ex){
System.out.println(ex.getMessage());
}
}
}
Post the discussion to improve the above solution.