Przejdź do głównej zawartości

Java -Arrays

Array - data structure that allows us to store multiple values of the same type into a single variable

Default value - zero
Arrays are zero indexed - Array with ten elements will be indexed from 0 to 9
Array[]

How to create array:

  1. int[] array = new int[5]; (boxes have value zero - secured slot in memory to hold values)
  2. int[] myArray = {1,2,3,4,5}; this type of initializing an array is also known as an anonymous array

boolean type arrays - default value is false

Errors while working with arrays


  1. ArrayIndexOutOfBoundsExeption

  2. int[] my Array = {10,35,45,78,55}
    myArray[5] = 55; out of bound
    index 5 does not exist





  1. int[] myArray = {10,15,20,17,18};


  2. for (int i=1; i < myArray.lenght; i++) 

    System.out.println("value= " + myArray[i]

    it will return values from index 1

How to print out simple int array?
example:

int[] myArray = new int[2];myArray[0]=0;myArray[1]=1;


System.out.println("My array: " + 
        Arrays.toString(myArray));


static StringtoString(int[] a)
Returns a string representation of the contents of the specified array.


public class Arrays - This class contains various methods for manipulating arrays (such as sorting and searching). This class also contains a static factory that allows arrays to be viewed as lists.

Komentarze

Popularne posty z tego bloga

Skrócony zapis if - instrukcja warunkowa java

Instrukcja warunkowa - warunek i rezultat. if (warunek) { jesli spełniony wykonań operacje i zwróć wynik; } warunek nie spełniony Możliwości skrócenia kodu instrukcji warunkowej if (i < 0) ? i-- : i++; Jeżeli i mniejsze od zera to i-- jezeli false to i++ if (i < 0) {     i--; } else {     i++; } Skrócony zapis instrukcji warunkowej else if (i < 0) ? i--;  inna_zmienna=4; : i++; if (i < 0) {     i--; } else {     i++;     inna_zmienna = 4; } Skrócony zapis if

String-2 > xyzThere - java

Return true if the given string contains an appearance of "xyz" where the xyz is not directly preceeded by a period (.). So "xxyz" counts but "x.xyz" does not.  xyzThere("abcxyz") → true xyzThere("abc.xyz") → false xyzThere("xyz.abc") → true Definiujemy loop ktory sprawdza za kazdym podejsciem czy kolejne indexy i,i+1 oraz i+2 i zdefiniowane dla nich char.  Nalezy tu pamietac ze jesli sprawdamy po indeksach np i+2 to tzreba zostawic "miejsce" na koncu aby nie bylo outOfBoudnExeption tj przekroczenia rlugosci stringa. Jezeli pierwszy warunek jest spelniony tj mamy na kolejnych indexach interesujace nas char-y sprawdzamy czy na poprzedzajacych nasza trojkę indexach pojawia sie "." zaczynamy od indexu 0 - tzreba to uwzglednić w warunku tj albo index 0 == 0 lub i-1 == 0 public boolean xyzThere ( String str ) { int len = str . length () - 2 ; for ( int i = 0 ; i < len ; i...

Learning by doing - Java - 50+ Interview Questions for Programmers

Learning by doing - Java - 50+ Interview Questions for Programmers 50+ Interview questions for 50+ days ? We will see ;) Risky resolution but method "learning by doing" is great!! First are coming questions regarding Arrays: How do you find the missing number in a given integer array of 1 to 100? ( solution ) How do you find the duplicate number on a given integer array? ( solution ) How do you find the largest and smallest number in an unsorted integer array? ( solution ) How do you find all pairs of an integer array whose sum is equal to a given number? ( solution ) How do you find duplicate numbers in an array if it contains multiple duplicates? ( solution ) How are duplicates removed from a given array in Java? ( solution ) How is an integer array sorted in place using the quicksort algorithm? ( solution ) How do you remove duplicates from an array in place? ( solution ) How do you reverse an array in place in Java? ( solution ) How are duplicates remov...