Structures in C.pptx
Download as PPTX, PDF0 likes48 views
This document discusses structures in C programming. It defines what a structure is and how it is declared. A structure allows the grouping of different data types together under one name. It explains that a structure definition does not allocate memory, it only defines a new data type that is used to declare structure variables. Structure variables can then be declared and memory is allocated for them. The document provides examples of defining and declaring structures, assigning values to structure members, accessing structure members using dot and arrow operators, and passing structures by reference to functions.
![Structure Definitions
• struct information
– A struct cannot contain an instance of itself.
– Can contain a member that is a pointer to the same
structure type.
– A structure definition does not reserve space in memory
• Instead creates a new data type used to declare structure
variables.
• Declarations
– Declared like other variables:
Student oneStud, Stud[66], *SPtr;
– Can use a comma separated list:
struct Student {
char name [20];
char address [20];
}oneStud, Stud[66], *SPtr;](https://image.slidesharecdn.com/structuresinc-230507020413-3088e8aa/85/Structures-in-C-pptx-3-320.jpg)
![Structure Definitions
• Example
struct Student {
char name [20];
char address [20];
int rollno;
char class[5];
char year[20];
};
– struct introduces the definition for structure
Student
– Student is the structure name and is used to
declare variables of the structure type](https://image.slidesharecdn.com/structuresinc-230507020413-3088e8aa/85/Structures-in-C-pptx-6-320.jpg)
![Structure and Assignment operator
• The values of a structure variable can be assigned to
another structure variable of the same type using the
assignment operator.
• No pease meal copy is needed .
struct employee
{
char name[10] ;
int age ;
float salary ;
} ;](https://image.slidesharecdn.com/structuresinc-230507020413-3088e8aa/85/Structures-in-C-pptx-12-320.jpg)
![Typedef Example
typedef struct
{
char *first;
char *last;
char SSN[9];
float gpa;
char **classes;
} student;
student stud_a, stud[20] ,*sptr;](https://image.slidesharecdn.com/structuresinc-230507020413-3088e8aa/85/Structures-in-C-pptx-14-320.jpg)
![Point out the errors, if any, in the following programs:
main( ) {
struct
{
char name[25] ;
char language[10] ;
} ;
struct employee e = { "Hacker", "C" } ;
printf ( "n%s %d", e.name, e.language ) ;
}](https://image.slidesharecdn.com/structuresinc-230507020413-3088e8aa/85/Structures-in-C-pptx-15-320.jpg)
![What would be the output of the following
programs
struct gospel {
int num ;
char mess1[50] ;
char mess2[50] ;
} m1 = { 2, "If you are driven by
success", "make sure that it is
a quality drive“ } ;
main( )
{
struct gospel m2, m3 ;
m2 = m1 ;
m3 = m2 ;
printf ( "n%d %s %s", m1.num,
m2.mess1, m3.mess2 ) ;
}
display ( struct book *b )
{
printf ( "n%s %s %d", b->
name, b->author, b->callno
) ;
}
And here is the output...
Let us C YPK 101](https://image.slidesharecdn.com/structuresinc-230507020413-3088e8aa/85/Structures-in-C-pptx-16-320.jpg)
![Call by reference and structure
/* Passing address of a structure variable */
struct book
{
char name[25] ;
char author[25] ;
int callno ;
} ;
void main()
{
struct book b1 = { "Let us C", "YPK", 101 } ;
display ( &b1 ); }](https://image.slidesharecdn.com/structuresinc-230507020413-3088e8aa/85/Structures-in-C-pptx-17-320.jpg)
Structures in C.pptx
- 1. Structures in C Department of Computer Science and Engineering
- 2. Creation of structure variable • Definition structure. • Declaration structure variable and memory allocation.
- 3. Structure Definitions • struct information – A struct cannot contain an instance of itself. – Can contain a member that is a pointer to the same structure type. – A structure definition does not reserve space in memory • Instead creates a new data type used to declare structure variables. • Declarations – Declared like other variables: Student oneStud, Stud[66], *SPtr; – Can use a comma separated list: struct Student { char name [20]; char address [20]; }oneStud, Stud[66], *SPtr;
- 4. Uses of Structures • Data base management • Changing the size of the cursor • Clearing the contents of the screen • Placing the cursor at an appropriate position on screen • Drawing any graphics shape on the screen • Receiving a key from the keyboard • Checking the memory size of the computer • Finding out the list of equipment attached to the computer • Formatting a floppy • Hiding a file from the directory • Displaying the directory of a disk • Sending the output to printer • Interacting with the mouse
- 5. Syntax Structure definition • struct <structure name> { structure element 1 ; structure element 2 ; structure element 3 ; ...... ...... } ;
- 6. Structure Definitions • Example struct Student { char name [20]; char address [20]; int rollno; char class[5]; char year[20]; }; – struct introduces the definition for structure Student – Student is the structure name and is used to declare variables of the structure type
- 7. Declaration of Struct variable • struct book { char name ; float price ; int pages ; } b1, b2, b3 ; Strut { char name ; float price ; int pages ; } b1, b2, b3 ; struct book { char name ; float price ; int pages ; } ; struct book b1, b2, b3
- 8. Assignment statements – Example: Student S2 = S1; – Could also declare and initialize threeHearts as follows: Student S2; S2.name = “Ashish”; S2.address = “Pune”; S2.rollno = 2543; S2.class = “SEV”; s2.year=“ 2012-1013”;
- 9. Accessing Members of Structures • Accessing structure members – Dot operator (.) used with structure variables Studnt S1; printf( "%s", S1.name ); – Arrow operator (->) used with pointers to structure variables Studnt *SPtr = &S1; printf( "%s", SPtr->name ); – SPtr->name is equivalent to ( *SPtr ).name;
- 10. Memory allocation /* Memory map of structure elements */ main( ) { struct book { char name ; float price ; int pages ; } ; struct book b1 = { 'B', 130.00, 550 } ; printf ( "nAddress of name = %u", &b1.name ) printf ( "nAddress of price = %u", &b1.price ) ; printf ( "nAddress of pages = %u", &b1.pages ) ; } Here is the output of the program... Address of name = 65518 Address of price = 65519 Address of pages =65523
- 12. Structure and Assignment operator • The values of a structure variable can be assigned to another structure variable of the same type using the assignment operator. • No pease meal copy is needed . struct employee { char name[10] ; int age ; float salary ; } ;
- 13. Structure and Assignment operator struct employee e1 = { "Sanjay", 30, 5500.50 } ; struct employee e2, e3 ; /* piece-meal copying */ strcpy ( e2.name, e1.name ) ; e2.age = e1.age ; e2.salary = e1.salary ; /* copying all elements at one go */ e3 = e2 ; printf ( "n%s %d %f", e1.name, e1.age, e1.salary ) ; printf ( "n%s %d %f", e2.name, e2.age, e2.salary ) ; printf ( "n%s %d %f", e3.name, e3.age, e3.salary ) ;
- 14. Typedef Example typedef struct { char *first; char *last; char SSN[9]; float gpa; char **classes; } student; student stud_a, stud[20] ,*sptr;
- 15. Point out the errors, if any, in the following programs: main( ) { struct { char name[25] ; char language[10] ; } ; struct employee e = { "Hacker", "C" } ; printf ( "n%s %d", e.name, e.language ) ; }
- 16. What would be the output of the following programs struct gospel { int num ; char mess1[50] ; char mess2[50] ; } m1 = { 2, "If you are driven by success", "make sure that it is a quality drive“ } ; main( ) { struct gospel m2, m3 ; m2 = m1 ; m3 = m2 ; printf ( "n%d %s %s", m1.num, m2.mess1, m3.mess2 ) ; } display ( struct book *b ) { printf ( "n%s %s %d", b-> name, b->author, b->callno ) ; } And here is the output... Let us C YPK 101
- 17. Call by reference and structure /* Passing address of a structure variable */ struct book { char name[25] ; char author[25] ; int callno ; } ; void main() { struct book b1 = { "Let us C", "YPK", 101 } ; display ( &b1 ); }
- 18. Any question?
- 19. THANKS ALL