Unit 4 cspc

CSPC-COMPUTER SYSTEMS
PROGRAMMING IN ‘C’
ANKUR SRIVASTAVA
DEPARTMENT OF COMPUTER SCIENCE
08/11/18ANKUR SRIVASTAVA ASSISTANT PROFESSOR JETGI
1

ARRAYS: ARRAY NOTATION AND REPRESENTATION,
MANIPULATING ARRAY ELEMENTS, USING MULTI-
DIMENSIONAL ARRAYS.
STRUCTURE, UNION, ENUMERATED DATA TYPES.
UNIT-4 TOPICS
2

UNIT-4 ARRAYS
 An arrayarray is a named collection of homogeneous items in which
individual items are accessed by their place within the collection.
 An arrayarray is a collection of variables of the same type that are referred
to by a common name.
Eg.
 product part numbers:
int part numbers[] = {123, 326, 178, 1209};
 student scores:
int scores[10] = {1, 3, 4, 5, 1, 3, 2, 3, 4, 4};
 characters:
char alphabet[5] = {’A’, ’B’, ’C’, ’D’, ’E’};
3

INITIALIZATION OF ARRAY
 Array – a set of elements all of the same type stored contiguously
in memory – e.g.,
 int A[25]; // 25 integers
 struct Str B[15]; /* 15 objects of
type struct Str */
 double C[]; /* indeterminate #
of doubles */
4

ARRAY NOTATION
5
An array of size N is indexed from zero to N-1
79 87 94 82 67 98 87 81 74 91scores
The entire array
has a single name
Each value has a numeric index
This array holds 10 values that are indexed from 0 to 9

MANIPULATING ARRAY ELEMENTS
 Some other examples of array declarations:
float[] prices = new float[500];
boolean[] flags;
flags = new boolean[20];
char[] codes = new char[1750];
6

2D ARRAY
7
 A one-dimensional array stores a list of elements
 A two-dimensional array can be thought of as a table of
elements, with rows and columns
one
dimension
two
dimensions

3D ARRAY
8
An array can be declared with multiple dimensions.
2 Dimensional 3 Dimensional
Multiple dimensions get difficult to visualize graphically.
•
int [][][] table3 = { { {1,2}, {3,4} },
{ {5,6,7} , {8}, {9,10}
}
};

USING MULTI-DIMENSIONAL ARRAYS
 An array can have many dimensions – if it has more than one
dimension, it is called a multidimensional array
 Each dimension subdivides the previous one into the specified
number of elements
 Each dimension has its own length constant
 Because each dimension is an array of array references, the
arrays within one dimension can be of different lengths
 these are sometimes called ragged arrays
9

MULTIDIMENSIONAL ARRAY
 Arrays with more than one index
 number of dimensions = number of indexes
 Arrays with more than two dimensions are a simple extension of
two-dimensional (2-D) arrays
 A 2-D array corresponds to a table or grid
 one dimension is the row
 the other dimension is the column
 cell: an intersection of a row and column
 an array element corresponds to a cell in the table
10

MULTI ARRAYS IMAGES
11

STRUCTURE:
 A structure is a collection of one or more components (members).
 Structures are called records in many other programming languages.
 Members are known as fields.
Declaring a structure:-
struct {
char name[25];
int id, age;
char sex;
} s1, s2;
12

INITIALIZING A STRUCTURE:-
struct {
char name[25];
int id, age;
char sex;
}
s1 = { "Smith, John", 2813, 25, 'M'},
s 2 = { "Smith, Mary", 4692, 23, 'F'};
13

ACCESSING THE MEMBERS OF A STRUCTURE:
 The members of a structure are accessed by writing first the name
of the structure, then a period, then the name of the member:
struct student {
char name[25];
int id, age;
char sex;
} s;
strcpy(s.name, "Doe, John");
s.id = 18193;
s.age = 18;
s.sex = 'M';
14

Some More Examples
15

Contd…..
16

INITIALIZATION OF STRUCTURE ARRAYS
 Structure arrays are initialized by enclosing the list of values of its
elements within a pair of braces.
 Example:
struct unit
{ char ch ;
int i ;
} ;
struct unit series [3]=
{ (‘a’, 100) (‘b’, 200) (‘c’, 400)
};
17

UNION:
 A union is similar to a structure, except that its members are
overlaid (located at the same memory address).
 A union is like a structure in which all members are stored at the
same address.
 Example:
union {
int i;
double d;
} u;
18

ACCESSING THE MEMBER
 The members of a union are accessed in the same way as members of
a structure:
u.i = 15;
or
u.d = 8.89;
Since u.i and u.d have the same memory address, changing the value
of one alters the value of the other.
19

Difference Between Structure & Union
20
// declaring structure
struct struct_example
{
int integer;
float decimal;
char name[20];
};
// declaring union
union union_example
{
    int integer;
    float decimal;
    char name[20];
};

Contd….
21

DIFFERENCE IN STORAGE OF UNION AND
STRUCTURE
22

Contd……..
23

ENUMERATED DATA TYPES
08/11/18
ANKUR SRIVASTAVA ASSISTANT PROFESSOR JETGI
24

ENUM DATA TYPES
25

Unit 4 cspc

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Unit 4 cspc