If a variable is a pointer to a structure, then which of the following operator is used to access data members of the structure through the pointer variable?

In C and C++, when a variable is a pointer to a structure, the operator used to access the data members of the structure through the pointer variable is the "arrow operator" (->).

Explanation:

1. Pointer to Structure: When you have a pointer that points to a structure, you cannot use the dot operator (.) to access the members directly because the pointer does not hold the structure itself; it holds the address of the structure instead.

2. Arrow Operator (->): The arrow operator is specifically designed to dereference a pointer and access its data members. For example, if you have a pointer ptr that points to a structure structName, you can access a member memberName using ptr->memberName. This effectively dereferences the pointer and accesses the member in one operation.

Example:

struct Employee {
    char name[50];
    int age;
};

struct Employee emp;
struct Employee *ptr = &emp;

// Accessing member using pointer
ptr->age = 30; // Assigns 30 to age member of emp struct

Final Answer:

The operator used to access data members of a structure through a pointer variable is the arrow operator (->).