C Programming

When we do not know what type of memory address the pointer variable is going to hold, then we declare a void pointer for such.

Yes, by holding the base address of the array into a pointer, we can access the array using a pointer.

We cannot use & on constants and on a variable that is declared using the register storage class.

The structure is defined as a user-defined data type that is designed to store multiple data members of the different data types as a single unit. A structure will consume the memory equal to the summation of all the data members.

struct employee
{
    char name[10];
    int age;
}e1;
int main()
{
    printf("Enter the name");
    scanf("%s",e1.name);
    printf("n");
    printf("Enter the age");
    scanf("%d",&e1.age);
    printf("n");
    printf("Name and age of the employee: %s,%d",e1.name,e1.age);
    return 0;
}

A structure containing an element of another structure as its member is referred to as a nested structure.

A structure containing the same structure pointer variable as its element is called a self-referential structure.

Yes, with respect to the order of structure elements only.

The union is a user-defined data type that allows storing multiple types of data in a single unit. However, it doesn't occupy the sum of the memory of all members. It holds the memory of the largest member only.

In a union, we can access only one variable at a time as it allocates one common space for all the members of a union.

Syntax of union:

union union_name  
{  
Member_variable1;  
Member_variable2;  
.  
.  
Member_variable n;  
}[union variables];

Arrow Operator( -> ) can be used to access the data members of a Union if the Union Variable is declared as a pointer variable.

In C, every local variable of a function is known as an automatic (auto) variable. Variables which are declared inside the function block are known as a local variable. The local variables are also known as auto variables. It is optional to use an auto keyword before the data type of a variable. If no value is stored in the local variable, then it consists of a garbage value.