4 Arrays In 'c' Ppt

Day – 3.

Arrays in ‘C’

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Arrays ) Introducing

Arrays ) Declaring Array Variables, Creating Arrays, and Initializing Arrays ) Passing Arrays to Methods ) Copying Arrays ) Multidimensional Arrays ) Search and Sorting Methods

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Introducing Arrays Array is a data structure that represents a collection of the same types of data. int num[10]; num

reference

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num [0] num [1] num [2] num [3] num [4] num [5] num [6] num [7] num [8] num [9]

An Array of 10 Elements of type int

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Declaring Array Variables ) datatype

arrayname[index];

Example:

int list[10]; char num[15]; float hat[20];

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Creating Arrays datatype array-name[size]; Example: int num[10]; num[0] references the first element in the array. num[9] references the last element in the array. 22-Jul-2008

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Declaring and Creating in One Step ) datatype

arrayname[arraySize]= {values seperated by comma}; Example : char c[5] = {‘a’,’F’,’4’,’’=‘,’n’}; int i[4] = {12,15,0,2};

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The Length of Arrays ) Once

an array is created, its size is fixed. It cannot be changed.

For example, int arr[10]; You can not insert any number to arr[11] location because it is not initialized.

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Initializing Arrays ) Declaring,

creating, initializing in one step:

float hat[4] = {1.9, 2.9, 3.4, 3.5};

This shorthand syntax must be in one statement.

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Declaring, creating, initializing Using the Shorthand Notation float list[4] = {1.9, 2.9, 3.4, 3.5};

This shorthand notation is equivalent to the following statements: float list[4]; list[0] = 1.9; list[1] = 2.9; list[2] = 3.4; list[3] = 3.5; 22-Jul-2008

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CAUTION Using the shorthand notation, you have to declare, create, and initialize the array all in one statement. Splitting it would cause a syntax error. For example, the following is wrong: float list; list = {1.9, 2.9, 3.4, 3.5};

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Example: Copying Arrays The program simply creates two arrays and attempts to copy one to the other, using an assignment statement.

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Copying Arrays Before the assignment list2 = list1; list1

list2

Contents of list1

Contents of list2

After the assignment list2 = list1; list1

list2

Contents of list1

Contents of list2

Garbage

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Copying Arrays With direct assignment: int array1[5] = {2, 3, 1, 5, 10}; int array2[5]; array2 = array1;

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Multidimensional Arrays Declaring Variables of Multidimensional Arrays and Creating Multidimensional Arrays int matrix[10][10]; for (i=0; i<10; i++) for (j=0; j<10; j++) { matrix[i][j] = i * j; } float mat[5][5]; 22-Jul-2008

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Multidimensional Array Illustration 0 1 2 3 4

0 1 2 3 4

0

1

2

2

3

0

0

0

1

1

1

4

5

6

2

2

2

7

8

9

3

3

10

11

12

4

4

int matrix[5][5];

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matrix[2][1] = 7;

3

1

int[][] array ={ {1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12}};

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Shorthand Notations You can also use a shorthand notation to declare, create and initialize a two-dimensional array. For example, int[][] array = { {1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {10, 11, 12} };

This is equivalent to the following statements: array[0][0] array[1][0] array[2][0] array[3][0]

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= = = =

1; array[0][1] = 2; array[0][2] = 4; array[1][1] = 5; array[1][2] = 7; array[2][1] = 8; array[2][2] = 10; array[3][1] = 11; array[3][2]

3; 6; 9; = 12;

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Ragged Arrays Each row in a two-dimensional array is itself an array. So, the rows can have different lengths. Such an array is known as a ragged array. For example, int[][] matrix = { {1, 2, 3, 4, 5}, {2, 3, 4, 5}, {3, 4, 5}, {4, 5}, {5} }; 22-Jul-2008 17

Exercise : Bubble Sort int i[] = {2, 9, 5, 4, 8, 1, 6}; // Unsorted Pass 1: Pass 2: Pass 3: Pass 4: Pass 5: Pass 6: 22-Jul-2008

2, 5, 4, 8, 1, 6, 9 2, 4, 5, 1, 6, 8, 9 2, 4, 1, 5, 6, 8, 9 2, 1, 4, 5, 6, 8, 9 1, 2, 4, 5, 6, 8, 9 1, 2, 4, 5, 6, 8, 9 18

Created By, ) Mr.

Tushar B Kute,

Lecturer in Information Technology, K. K. Wagh Polytechnic, Nashik. [email protected]

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