Advanced Computer Programming

Transcription

1 Hazırlayan Yard. Doç. Dr. Mehmet Fidan

2 SUMMARY: INDEX NUMBERS int[] day = new int[7]; day[0] day[1] day[2] day[3] day[4] day[5] day[6] Examples: day[5] = 1; if( day[5] == 4 ) break; day[5] = day[6] - 1;

3 SUMMARY: EXAMPLE Variable i will take values from 0 to 6 within for loop

4 SUMMARY: INITIALIZATION OF ARRAYS As in the case of variables, we could also set initial values to the arrays in the definition phase. static void Main(string[] args) { int[] day = { 0,2,4,6,8,10,11 };... }

5 SUMMARY: INITIALIZATION OF ARRAYS static void Main(string[] args) { int[] day = { 0,2,4,6,8,10,11 };... } Compiler counts the integer values and decides the value in the[] brackets is 7 and compiles the program as int[] gun = new int[7]

6 SUMMARY: EXAMPLE Define an array of double type that has 10 elements, then assign values between 1.0 and Finally swap elements at 0 and 9 with each other. static void Main(string[] args) { double[] arr = {1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0}; double tmp; tmp = arr[9]; arr[9] = arr[0]; arr[0] = tmp; }

7 SUMMARY: Array.Length() Used in finding the length of the array. Called right after the. mark after the array name. int[] myarray = new int[5]; int len = myarray.length(); Console.WriteLine(len); Output : 5

8 SUMMARY: Foreach Loop foreach and for loops can be converted to each other.

9 SUMMARY: STANDARD MULTIDIMENSIONAL ARRAYS Creation of multidimensional arrays are similar to one dimensional ones. The difference is there is a comma between the square brackets. int [,] numbers; string [,,] lines; As an example, a string type two by three multidimensional array can be created with string[,] array = new string[2,3];

10 STANDARD MULTIDIMENSIONAL ARRAYS Lets create a 2D multidimensional array and assign values to its elements in a loop.

11 SUMMARY: Array.IndexOf() Array.LastIndexOf() Result : 1 Result : 4

12 SUMMARY: Array.Sort() Sorts the elements of the array by ascending order. Result : Ali Mehmet Pınar Zeynep

13 SUMMARY: Array.Reverse() Reverses the order of the elements of the array. Result : Not : Array.Sort and Array.Reverse does not have to be used together.

14 Problem If we don t know the size of the array in advance? What if array expands dynamically?

15 COLLECTIONS Used in situations of which the length of the array is not known in advance. Or the length of the array grows or shrinks dynamically. They are one dimensional.

16 ArrayList It is one of the basic collection types. Resides in System.Collections namespace. It has initial length of 16 and for each expansion, its length is multiplied by 2. Stores data as type of object.

17 ArrayList Creating a new ArrayList: ArrayList list = new ArrayList(); Example

18 ArrayList Important functions and properties Add RemoveAt Capacity Reverse Clear Sort Count TrimToSize IndexOf Insert

19 EXERCISE Define an ArrayList to hold the names of staff. Add the names; Ahmet, Mehmet, Pınar, Yeşim, Utku, Sinan, Fatma, Ayşe to the list. Print the list and its size to output. Delete the elements which are stating with letter A from the list Sort the list with reverse order. Print the list and its size to output.

20 EXERCISE

21 COLLECTIONS Used in situations of which the length of the array is not known in advance. Or the length of the array grows or shrinks dynamically. They are one dimensional.

22 ArrayList It is one of the basic collection types. Resides in System.Collections namespace. It has initial length of 16 and for each expansion, its length is multiplied by 2. Stores data as type of object.

23 ArrayList Creating a new ArrayList: ArrayList list = new ArrayList(); Example

24 ArrayList Important functions and properties Add RemoveAt Capacity Reverse Clear Sort Count TrimToSize IndexOf Insert

25 EXERCISE Define an ArrayList to hold the names of staff. Add the names; Ahmet, Mehmet, Pınar, Yeşim, Utku, Sinan, Fatma, Ayşe to the list. Print the list and its size to output. Delete the elements which are stating with letter A from the list Sort the list with reverse order. Print the list and its size to output.

26 EXERCISE