Java Code Example: largest number in an array

The code defines a Java program to find the largest number in an array of integers.

The program starts by initializing a Scanner object to read input from the user. Then it creates an array of 20 integers named numbers.

The program then prompts the user to enter the number of values they want to store in the array. This value is stored in the quantity variable.

A for loop is then used to read quantity numbers from the user and store them in the numbers array.

After all the numbers have been entered, the Scanner object is closed.

Next, the variable currentNumber is initialized with the first number in the numbers array. A for loop is then used to iterate over the numbers array, starting from the second position (i=1) and ending at i=quantity. In each iteration, the code checks if the current value of currentNumber is less than the value of the current array element (numbers[i]). If it is, then the value of currentNumber is updated to be the value of numbers[i].

After the loop has completed, the code prints out the value of currentNumber, which is the largest number in the array.

import java.util.Scanner;

public class LargestNumberInArray {
	public static void main(String[] args) {
		Scanner reader = new Scanner(System.in);
		int[] numbers = new int[20];
		int i = 0, currentNumber, quantity;

		System.out.print("How many numbers do you want to store in array? (1 - 20): " );
		quantity = reader.nextInt();

		// Store numbers in array (user input)
		for(i = 0 ; i < quantity ; i++) {
			System.out.println("Please enter a number: ");
			numbers[i] = reader.nextInt();
		}

		reader.close();
		
		currentNumber = numbers[0];

		// loop over array and store largest number in first array position
		for(i = 1; i < quantity; i++) {
			if(currentNumber < numbers[i]) {
				currentNumber = numbers[i];
			}
		}

		System.out.println("Largest number in array is: " + currentNumber);
	}
}

Output

How many numbers do you want to store in array? (1 - 20): 5
Please enter a number: 
1
Please enter a number: 
2
Please enter a number: 
3
Please enter a number: 
4
Please enter a number: 
5
Largest number in array is: 5