J. Introducere in limbajul Java - Discipline
J. Introducere in limbajul Java - Discipline
J. Introducere in limbajul Java - Discipline
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Curs SwRTc (draft) 2004-2005 33/34 10/22/2006 2006_Intro_<strong>Java</strong>_v01.htm<br />
J.4.4.5. Exemple de lucru cu variabile de tip tablou cu elemente de tip refer<strong>in</strong>ta<br />
Urmatorul program afiseaza numarul de caractere al sirurilor de caractere cont<strong>in</strong>ute <strong>in</strong> tabloul<br />
tablouSiruri, exemplificand lucrul cu un tablou de refer<strong>in</strong>te la obiecte Str<strong>in</strong>g.<br />
public class AfisareTablouSiruri {<br />
public static void ma<strong>in</strong>(Str<strong>in</strong>g[] args) {<br />
Str<strong>in</strong>g[] tablouSiruri = {"Primul sir", "Al doilea sir", "Al treilea sir "};<br />
}<br />
}<br />
for (<strong>in</strong>t <strong>in</strong>dex = 0; <strong>in</strong>dex < tablouSiruri.length; <strong>in</strong>dex++) {<br />
System.out.pr<strong>in</strong>tln(tablouSiruri[<strong>in</strong>dex].length());<br />
}<br />
Se poate observa diferenta d<strong>in</strong>tre modul de a obt<strong>in</strong>e numarul de elemente al unui tablou,<br />
folos<strong>in</strong>d variabila sa membru length, si modul de a obt<strong>in</strong>e lungimea numarul de caractere al unui sir<br />
de caractere Str<strong>in</strong>g, folos<strong>in</strong>d metoda sa length().<br />
Urmatorul program creeaza, populeaza si apoi afiseaza elementele unui matrice, exemplificand<br />
lucrul cu un tablou de tablouri cu elemente de tip primitiv <strong>in</strong>t.<br />
public class PopulareSiAfisareMatriceIntregi {<br />
public static void ma<strong>in</strong>(Str<strong>in</strong>g[] args) {<br />
}<br />
}<br />
// crearea matricii<br />
<strong>in</strong>t[][] matrice = new <strong>in</strong>t[4][]; // crearea tabloului<br />
// popularea matricii<br />
for (<strong>in</strong>t i=0; i < matrice.length; i++) { // matrice.length = 4<br />
matrice[i] = new <strong>in</strong>t[5]; // crearea sub-tablourilor<br />
for (<strong>in</strong>t j=0; j < matrice[i].length; j++) {<br />
matrice[i][j] = i+j; // <strong>in</strong>itializarea elementelor sub-tablourilor<br />
}<br />
}<br />
// afisarea matricii<br />
for (<strong>in</strong>t i=0; i < matrice.length; i++) {<br />
for (<strong>in</strong>t j=0; j < matrice[i].length; j++) {<br />
System.out.pr<strong>in</strong>t(matrice[i][j] + " ");<br />
}<br />
System.out.pr<strong>in</strong>tln();<br />
}<br />
Tabloul matrice cont<strong>in</strong>e un numar de matrice.length = 4 tablouri, fiecare d<strong>in</strong>tre ele avand un<br />
numar de matrice[i].length = 5 elemente.<br />
Sub-tablourile pot fi accesate <strong>in</strong>dividual folos<strong>in</strong>d s<strong>in</strong>taxa matrice[i], iar elementele tabloului i<br />
pot fi accesate folos<strong>in</strong>d s<strong>in</strong>taxa matrice[i][j]. Elementul matrice[0][2] reprez<strong>in</strong>ta, de exemplu, al<br />
treilea element al primului tablou, iar elementul matrice[2][0] reprez<strong>in</strong>ta primul element al celui deal<br />
treilea tablou.<br />
Se observa ca mai <strong>in</strong>tai a fost declarat, alocat si <strong>in</strong>itializat tabloul matrice, apoi au fost alocate si<br />
<strong>in</strong>itializate cele 4 sub-tablouri, si abia apoi au fost populate cu valori.