Question

I’m new to Java and I’m trying to make a program that allows the user to input 100 numbers and if the user writes ‘0’, then the program is suppose to print the smallest, largest, sum and all the numbers. I got all that to work but not to exit and print it all. My teacher said something about using a while loop, but how is that possible when you have a for loop?

Regards

public static void main(String[] args) {
    int[] list = new int[100];
    int min = 0;
    int max = 0;
    int sum = 0;
    boolean first = true;

    Scanner scan = new Scanner(System.in);
    while(list[i] != 0) {
        for (int i = 0; i < list.length; i++) {

            System.out.print("Enter number (0 to exit) " + (1 + i) + ":");
            list[i] = scan.nextInt();
        }

        for (int i = 0; i < list.length; i++) {

            if (first == true) {

            min = list[i];
            first = false;
        }

        if (list[i] < min) {

            min = list[i];
        }

        else if (list[i] > max) {

            max = list[i];
        }

        sum = list[i] + sum;

    }

    if (list[i] == 0) {

    System.out.print("Numbers are: " + list[0] + ", ");

    for (int i = 1; i < list.length; i++)

    System.out.print(list[i] + ", ");
    System.out.println();

    System.out.println("Smallest number is: " + min);
    System.out.println("Largest numeber is: " + min);
    System.out.println("Sum is: " + sum);
    }
    }
}

}

Answer 1

Here’s the body of the method which will do what you’ve been asked. I have not used a while loop (but in fact, a for-loop is a kind of a while-loop internally).

int size = 100; // Set the number of numbers to input.
int[] list = new int[size]; // Create an array with 'size' elements.
int min = Integer.MAX_VALUE; // Set the highest possible integer as start value.
int max = 0; // Set the minimum to zero, assuming that the user won't input negative numbers.
int sum = 0; // Initialize the sum of the numbers in the list.

Scanner scan = new Scanner(System.in);

for (int i = 0; i < size; i++) { // Run 'size' times the process of inputting a number.
    System.out.print("Enter number (0 to exit) " + (i + 1) + ": ");
    int number = scan.nextInt();
    if (number == 0) { // Quit program if input equals '0'
        System.out.println("Exiting...");
        break;
    }
    list[i] = number; // Add the current number to the list
    sum += number; // Add the number to the total
    if (number < min) { // If the number is smaller than the previous one, set this number as the smallest
        min = number;
    }
    if (number > max) { // If the number is greater than the previous smallest number, set this number as the greatest
        max = number;
    }
}

// Output all numbers in the list
for (int i = 0; i < list.length; i++) {
    if (list[i] != 0) {
        System.out.print((i == 0 ? "" : ", ") + list[i]);
    }
}

// You see the snippet (i == 0 ? "" : ", ")
// That is a shorthand if-else statement:
// If i equals 0, then "" (empty string), else ", " (comma and space).
// The statement
//     System.out.print((i == 0 ? "" : ", ") + list[i])
// is the same as
//     if (i == 0) {
//         System.out.println("") + list[i];
//     }
//     else {
//         System.out.println(", ") + list[i];
//     }

System.out.println("Smallest number is: " + min);
System.out.println("Largest numeber is: " + max);
System.out.println("Sum is: " + sum);