How do you declare a pointer to an integer?

Explanation:

Declaring a Pointer to an Integer

Correct Option: 1) int *ptr;

Definition: In the C programming language, a pointer is a variable that stores the memory address of another variable. When you declare a pointer to an integer, you are creating a variable that can hold the address of an integer variable.

Syntax: The correct syntax to declare a pointer to an integer is int *ptr;. This statement declares a variable ptr as a pointer to an integer type. The asterisk (*) indicates that the variable is a pointer, and the type int specifies that the pointer will point to an integer.

Here is a breakdown of the correct option:

• int - This specifies the data type of the variable that the pointer will point to. In this case, it is an integer.
• * - The asterisk indicates that the variable being declared is a pointer.
• ptr - This is the name of the pointer variable.

Example: Below is a simple example demonstrating the declaration and usage of a pointer to an integer:

int main() {
    int number = 10; / Declare an integer variable
    int *ptr; / Declare a pointer to an integer

    ptr = &number; / Assign the address of the integer variable to the pointer

    printf("Value of number: %d\n", number); / Output the value of the integer variable
    printf("Address of number: %p\n", &number); / Output the address of the integer variable
    printf("Value stored in ptr: %p\n", ptr); / Output the address stored in the pointer
    printf("Value pointed to by ptr: %d\n", *ptr); / Output the value pointed to by the pointer

    return 0;
}

In this example, number is an integer variable, and ptr is a pointer to an integer. The address of number is assigned to ptr. The pointer ptr now holds the memory address of the integer variable number. The value pointed to by ptr can be accessed using the dereference operator (*).