What happens when you cast a pointer?

What happens when you cast a pointer?

Using pointer casting, a pointer to one type of value can be converted to a pointer to a different type without modifying anything. But the problem here is that the result may be undefined. This happens because different types of variables have different sizes, and they are aligned differently in memory.

Can we typecast pointers in C?

We saw that pointer values may be assigned to pointers of same type. However, pointers may be type cast from one type to another type. In the following code lines, A is an int type variable, D is variable of type double, and ch is a variable of type char.

Can you typecast a pointer?

Pointer is merely a memory address. With typecasting, any type with enough size to hold the memory address can work like a pointer.

What does casting a pointer mean?

A pointer is an arrow that points to an address in memory, with a label indicating the type of the value. The address indicates where to look and the type indicates what to take. Casting the pointer changes the label on the arrow but not where the arrow points.

How do I cast a void pointer?

Example program:- ptr=&a // Assigning address of integer to void pointer. printf(“The value of integer variable is= %d”,*( (int*) ptr) );// (int*)ptr – is used for type casting. Where as *((int*)ptr) dereferences the typecasted void pointer variable. ptr=&b // Assigning address of float to void pointer.

What is a void pointer?

A void pointer is a pointer that has no associated data type with it. A void pointer can hold address of any type and can be typcasted to any type.

Can a void pointer point to anything?

A void pointer is a pointer that can point to any type of object, but does not know what type of object it points to. A void pointer must be explicitly cast into another type of pointer to perform indirection.

What is null and void pointer?

NULL is a value that is valid for any pointer type. It represents the absence of a value. A void pointer is a type. Any pointer type is convertible to a void pointer hence it can point to any value.

What we Cannot do on a void pointer?

Explanation: Because the void pointer is used to cast the variables only, So pointer arithmetic can’t be done in a void pointer.

What is string * x y?

string* x, y; a. x is a pointer to a string, y is a string. b. y is a pointer to a string, x is a string.

What is size of void pointer?

8 bytes

Can pointer be initialized?

The initializer is an = (equal sign) followed by the expression that represents the address that the pointer is to contain. The following example defines the variables time and speed as having type double and amount as having type pointer to a double .

Which is the correct way to declare a pointer?

Explanation: int *ptr is the correct way to declare a pointer.

How do you access a value from a pointer?


  1. Declare a normal variable, assign the value.
  2. Declare a pointer variable with the same type as the normal variable.
  3. Initialize the pointer variable with the address of normal variable.
  4. Access the value of the variable by using asterisk (*) – it is known as dereference operator.

How do you turn a pointer into a variable?

The “address of” operator This is the best way to attach a pointer to an existing variable: int * ptr; // a pointer int num; // an integer ptr = &num // assign the address of num into the pointer // now ptr points to “num”!

What is pointer value?

A memory pointer (or just pointer) is a primitive, the value of which is intended to be used as a memory address; it is said that a pointer points to a memory address. It is also said that a pointer points to a datum [in memory] when the pointer’s value is the datum’s memory address.

What is pointer with example?

A pointer is a variable that stores the address of another variable. Unlike other variables that hold values of a certain type, pointer holds the address of a variable. For example, an integer variable holds (or you can say stores) an integer value, however an integer pointer holds the address of a integer variable.

What is Pointer and its types?

A pointer is nothing but a memory location where data is stored. A pointer is used to access the memory location. There are various types of pointers such as a null pointer, wild pointer, void pointer and other types of pointers. Pointers can be used with array and string to access elements more efficiently.

What pointer means?

1 : something that points or is used for pointing. 2 : a helpful hint I got a few pointers on diving.

What is dangling pointer in C?

Dangling pointer occurs at the time of the object destruction when the object is deleted or de-allocated from memory without modifying the value of the pointer. In this case, the pointer is pointing to the memory, which is de-allocated.

Why are dangling pointers bad?

A dangling pointer is a pointer to memory that your program should not use. Using dangling pointers is a common mistake among beginners. One kind of dangling pointer is an address in a part of memory that the OS knows does not belong to your process. Using such a dangling pointer leads to a memory fault.

How many types of pointer are there?

eight different types

What is a double pointer?

A pointer is used to store the address of variables. So, when we define a pointer to pointer, the first pointer is used to store the address of the second pointer. Thus it is known as double pointers.

How can I get a free double pointer?

So free works the same: just free the top-level pointer, because that is the only pointer that points to the block of memory that was created by malloc: double** x = (double**)malloc(sizeof(double*)*3);…For example:

  1. void *ptr = malloc(number_of_bytes);
  2. if (ptr == NULL) exit(EXIT_FAILURE);
  3. free(ptr);

Is a 2D array a double pointer?

2D array is NOT equivalent to a double pointer! 2D array is “equivalent” to a “pointer to row”. The information on the array “width” (n) is lost. o use an auxiliary array of pointers, o each of them points to a row of the original matrix.

How do I assign a pointer to another pointer?

Pointer assignment between two pointers makes them point to the same pointee. So the assignment y = x; makes y point to the same pointee as x . Pointer assignment does not touch the pointees. It just changes one pointer to have the same reference as another pointer.

Can two pointers point to same address?

Pointers are variables whose value is the address of a C object, or the null pointer.

  • multiple pointers can point to the same object: char *p, *q; p = q = “a”;
  • a pointer can even point to itself: void *p; p = &p

Can a pointer point to two address?

No, a single pointer can only point to one thing. That thing could be an int , or an array (or an element of an array), or some other thing. However, you can take a pointer and make it instead point to something else from then on! Like a different int , or a different element of an array.

Why would you have a pointer point to another pointer?

We already know that a pointer points to a location in memory and thus used to store the address of variables. So, when we define a pointer to pointer. The first pointer is used to store the address of the variable. And the second pointer is used to store the address of the first pointer.

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