Structure Frequently Asked Questions in C.

Q7.What is the size of a structure in C?
The size of a structure in C is the sum of the sizes of its members. The size of a structure type can be determined using the sizeof operator in C. The size of a structure is typically greater than or equal to the sum of the sizes of its individual members. The size calculation takes into account various factors, including data types, order of members, and compiler-specific padding requirements.
The size of a struct type can be determined using the sizeof operator in C. The size of a structure in C is the sum of the sizes of its members. The size of a struct is usually greater than or equal to the sum of the sizes of its individual members. The size calculation takes into account various factors, including element order, data types, and compiler-specific padding requirements.

Q8.How do you pass a structure to a function in C?
In C Language there are two way to pass structure to function:
1. Pass by value, passing actual value as argument.
2. Passing by reference, passing address of an argument.

Q9.Can a structure have functions in C?
A user-defined data type structure is used for storing data of the same or different data types. C does not allow us to declare a function inside a structure. This is mainly because C is a simple language and does not support object-oriented programming.

Q10.What is the purpose of typedef in relation to structures in C?
Typedef is a keyword used to give a new name to an existing data type. The C typedef keyword is used to redefine the names of existing data types.

Q11.How do you dynamically allocate memory for a structure in C?

in C,using some standard library function dynamic memory is allocated from heap. The two main functions of dynamic memory are malloc() and free(). Dynamically allocate storage for data as needed. The malloc() function takes a single parameter - the size of the requested memory area in bytes.
The function for allocating memory at run-time: malloc.
void *malloc(int numBytes);
It returns a generic pointer (void*) to a contiguous region of memory of the requested size (in bytes).
It returns a pointer to the allocated memory.

Q12.What is the difference between a structure and an array of structures in C?
ARRAY:
1.Array refers to a collection consisting of elements of homogeneous data type.
2.Array uses subscripts or “[ ]” (square bracket) for element access.
3.Array is pointer as it points to the first element of the collection.
4.Instantiation of Array objects is not possible.
5.The size of the array is static or fixed and essentially the number of elements multiplied by the size of the elements.
6.Bit field is not possible in an Array.
7.Array declaration is done simply using [] and not any keyword.
8.Arrays is a non-primitive datatype.
9.Array searching and traversal is fast and easy.
10.data_type array_name[size];
11.Array elements are stored in contiguous memory locations.
12.Array elements are accessed by their index number using subscripts.
STRUCTURE:
1.Structure refers to a collection consisting of elements of heterogeneous data type.
2.Structure uses “.” (Dot operator) for element access.
3.Structure is not a pointer.
4.Instantiation of Structure objects is possible.
5.Structure size is not fixed as each element of Structure can be of different type and size.
6.Bit field is possible in an Structure.
7.Structure declaration is done with the help of “struct” keyword.
8.Structure is a user-defined datatype.
9.Searching and traversal in structure is slow and complex.
10.struct sruct_name{ data_type1 ele1; data_type2 ele2; };
11.Structure elements may or may not be stored in a contiguous memory location.
12.Structure elements are accessed by their names using dot operator.

Q13.How do you compare two structures in C?
A structure comparison begins by comparing the number of elements in each structure list. If they are different the comparison stops here. If they have the same number of elements, each pair of individual structures is compared in the order in which they occur.

Q14.Can a structure have another structure as a member in C?
Yes. A structure inside another structure is called nesting of structures. Nested structures are allowed in the C programming language. We can write a structure inside another structure as a member of another structure.

Q15.How do you access a structure member using a pointer in C?.
There are two ways to access structure members using a structure pointer:
1.Using the asterisk (*) or indirect operator and dot (.) operator.
2.Using the arrow operator (->).

16.How do you define a constant structure in C? The const keyword is used before the structure definition To define a constant structure in C,
typedef struct {
int empno;
char ename[20];
} const employee = {100, "Ram"};

17.How do you declare an array of structures in C?
To declare an array of structures, you must first define the structure using the "struct" keyword and then specify the type identifier of the structure. Then create an array of structures using the identifier structure type.
Let's explain this with an example:
// Defining the structure
struct employee{
int empno;
char ename[100];
float salary;
};
// Declaring array of structures
struct employee emp[10];