Primo Giorno

import javax.swing.plaf.synth.SynthEditorPaneUI;

public class Main {

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

        int intProva = 3;
        double doubleProva = 3.3;
        char carattereDiProva = 'z';
        char charProva = carattereDiProva;
        boolean boolProva = true;

        int result = intProva * intProva;
        double resultDouble = intProva + doubleProva;


        String[] a1 = new String[4];
        int[] a2 = new int[3];
        double[] a3 = new double[5];

        a1[0] = "ciao";
        a1[1] = "sono";
        a1[2] = "un'";
        a1[3] = "array";

        a2[0] = 2;
        a3[0] = 2.5;

        System.out.println(a3[0]);


        //char primoCarattere = stringaProva.charAt(0);
        char primoCarattere = getFirstChar(stringaProva);
        System.out.println(primoCarattere);


        boolean valore = existChar(stringaProva,'?');
        System.out.println(valore);

        System.out.println("----------------------------------");

        System.out.println(getCharPosition(stringaProva,'o'));

        stampaArray(getCharPositions(stringaProva,'?'));


    }

    //tipoDiRitorno nomeMetodo(parametro 1,...,n)

    public static char getFirstChar(String stringa){
        char result = ' ';
        char[] arrayDiCaratteri = stringa.toCharArray();
        result = arrayDiCaratteri[0];
        return result;
    }

    public static boolean existChar(String stringa,char character) {

        char[] arrayC = stringa.toCharArray();
        int i;
        for(i = 0;i<stringa.length();i++) {
            if (arrayC[i] == character) {
                return true;
            }
        }
        return false;
    }

    public static int getCharPosition(String s,char c) {
        int r = -1;
        char[] aC = s.toCharArray();
        boolean e = existChar(s,c);
        if (e == false) {
            return r;
        }
        int i;
        for(i=0;i<s.length();i++) {
            if(c==aC[i]) {
                r = i;
            }
        }
        return r;
    }

    public static int[] getCharPositions(String s,char c) {

        int[] arrayResult = new int[s.length()];

        int r = -1;
        char[] aC = s.toCharArray();
        boolean e = existChar(s,c);
        if (e == false) {
            arrayResult[0] = r;
            return arrayResult;
        }
        int i;
        int count = 0;
        for(i=0;i<s.length();i++) {
            if(c==aC[i]) {
                arrayResult[count] = i;
                count++;
            }
        }
        return arrayResult;
    }

    public static void stampaArray(int[] a) {
        System.out.print("[");
        for(int i=0;i<a.length - 1;i++) {
            System.out.print(" "+a[i]+" ");
        }
        System.out.print("]");
    }


}