![ A structure value is a collection of smaller values called member values.
There is one member value for each member name declared in the structure definition.
A structure definition is usually placed outside of any function definition. The structure type is then available to all the code that
follows the structure definition.
struct Structure_Tag
{
Type_1 Member_Variable_Name_1;
Type_2 Member_Variable_Name_2;
.
.
.
Type_Last Member_Variable_Name_Last;
}[variablename,anothervariableifany]; // }[variablename,anothervariableifany] is optional
Variables of a structure type can be declared in the same way as variables of other types.
struct course{
string coursename;
string ccode;
int Ects, Chour;
};](https://image.slidesharecdn.com/structure-230604145054-b73bd39c/85/Structure-pptx-3-320.jpg)
![struct Date
{
int month;
int day;
int year;
};
struct PersonInfo
{
double height;//in inches
int weight;//in pounds
Date birthday;
};
PersonInfo person1;
cout << person1.birthday.year;
POINTERS TO ACCESS DATA WITHIN A STRUCTURE.
Date *d;
(*d).month=12;
D-->month=12;
Student * members = new student[100];
//contributions is a structure;
members[i].batch=2009;
Or
*(members+i)-->batch= 2009;
members[i]->batch= 2009; //Using both [] and -> doesn't work
because then you'd be dereferencing twice.](https://image.slidesharecdn.com/structure-230604145054-b73bd39c/85/Structure-pptx-8-320.jpg)
![ARRAY OF STRUCTURES
It is possible to have an array of structures. As StructureName arrayName[size];
To access arrayName[index].memebervariable
Struct student {
. . .
. . .
} st[100];
To access members you can use st[0].member=value;
e.g.
personInfo persons[100];
persons[0].height=1.83;
persons[5].weight=75;](https://image.slidesharecdn.com/structure-230604145054-b73bd39c/85/Structure-pptx-9-320.jpg)
Structure.pptx
- 2. Data structures are a feature that can be used to represent databases, especially if we consider the possibility of building arrays of them: The structure tag can be any legal identifier (but not a keyword). The name of a structure type is called the structure tag. The identifiers declared inside the braces,{ }, are called member names. A structure type definition ends with both a brace, }, and a semicolon. Once a structure type definition has been given, the structure type can be used just like the predefined types int, char, and so forth. A structure variable can hold values just like any other variable can hold values.
- 3. A structure value is a collection of smaller values called member values. There is one member value for each member name declared in the structure definition. A structure definition is usually placed outside of any function definition. The structure type is then available to all the code that follows the structure definition. struct Structure_Tag { Type_1 Member_Variable_Name_1; Type_2 Member_Variable_Name_2; . . . Type_Last Member_Variable_Name_Last; }[variablename,anothervariableifany]; // }[variablename,anothervariableifany] is optional Variables of a structure type can be declared in the same way as variables of other types. struct course{ string coursename; string ccode; int Ects, Chour; };
- 4. INITIALIZATION Struct Date{ int day, month,year; }; Date due_date = {12, 31, 2004}; Date anotherDate=due_date; It is an error if there are more initializers than struct members. If there are fewer initializer values than struct members, the provided values are used to initialize data members, in order. Each data member without an initializer is initialized to a zero value of an appropriate type for the variable.
- 5. The structure type is then available to all the code that follows the structure definition. Two or more structure types may use the same member names. struct FertilizerStock { double quantity; double nitrogen_content; }; struct CropYield { int quantity; double size; }; This coincidence of names will produce no problems. Why?
- 6. The dot operator is used to specify a member variable of a structure variable. Structure_Variable_Name.Member_Variable_NameEXAMPLES Structure_Variable_Name.Member_Variable_Name EXAMPLES struct StudentRecord { int student_number; char grade; }; int main( ) { StudentRecord your_record; your_record.student_number = 2001; your_record.grade = 'A'; Some writers call the dot operator the structure member access operator although we will not use that term.
- 7. You must also place a semicolon after that final brace. A structure definition is more than a definition. It can also be used to declare structure variables. A function can have call-by-value parameters of a structure type and/or call by-reference parameters of a structure type. A function can have call-by-value parameters of a structure type and/or call by- reference parameters of a structure type. A structure type can also be the type for the value returned by a function. Sometimes it makes sense to have structures whose members are themselves smaller structures.
- 8. struct Date { int month; int day; int year; }; struct PersonInfo { double height;//in inches int weight;//in pounds Date birthday; }; PersonInfo person1; cout << person1.birthday.year; POINTERS TO ACCESS DATA WITHIN A STRUCTURE. Date *d; (*d).month=12; D-->month=12; Student * members = new student[100]; //contributions is a structure; members[i].batch=2009; Or *(members+i)-->batch= 2009; members[i]->batch= 2009; //Using both [] and -> doesn't work because then you'd be dereferencing twice.
- 9. ARRAY OF STRUCTURES It is possible to have an array of structures. As StructureName arrayName[size]; To access arrayName[index].memebervariable Struct student { . . . . . . } st[100]; To access members you can use st[0].member=value; e.g. personInfo persons[100]; persons[0].height=1.83; persons[5].weight=75;