Letný semester, prednáška č. 1

Prvý program v jazyku Java

Tradične začneme programom, ktorý na konzolu vypíše text Hello, World!.

public class Hello {

    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }

}

package hello;

public class Hello {

    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }

}

Nič nové pod Slnkom...

import java.util.*;

public class Program {

    /* Spocita sucet prvkov pola a.
     */
    public static int sum(int[] a) {
        int result = 0;
        for (int i = 0; i <= a.length - 1; i++) {
            result += a[i];
        }
        return result;
    }

    /* Spocita priemer hodnot prvkov pola a.
     */
    public static double average(int[] a) {
        return (double) sum(a) / a.length;
    }

    /* Najde najvacsi prvok pola a.
     */
    public static int max(int[] a) {
        int max = Integer.MIN_VALUE;  // Premenna ma rovnaky nazov ako metoda
        for (int i = 0; i <= a.length - 1; i++) {
            if (a[i] >= max) {
                max = a[i];
            }
        }
        return max;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        int n = scanner.nextInt();
        int[] a = new int[n];

        for (int i = 0; i <= n - 1; i++) {
            a[i] = scanner.nextInt();
        }
        scanner.close();

        System.out.println("Sucet: " + sum(a));
        System.out.println("Priemer: " + average(a));
        System.out.println("Maximum: " + max(a));
    }

}