What Does Void * Mean?

Can we write void main in C++?

On systems that doesn’t provide such a facility the return value is ignored, but that doesn’t make “void main()” legal C++ or legal C.

Even if your compiler accepts “void main()” avoid it, or risk being considered ignorant by C and C++ programmers.

In C++, main() need not contain an explicit return statement..

Why do we typecast malloc?

Advantages to casting: The cast allows for pre-1989 versions of malloc that originally returned a char * . Casting can help the developer identify inconsistencies in type sizing should the destination pointer type change, particularly if the pointer is declared far from the malloc() call.

Why do we need void pointer?

The void pointer in C is a pointer which is not associated with any data types. It points to some data location in the storage means points to the address of variables. It is also called general purpose pointer. In C, malloc() and calloc() functions return void * or generic pointers.

What does NULL pointer do?

A null pointer is a pointer which points nothing. Some uses of the null pointer are: a) To initialize a pointer variable when that pointer variable isn’t assigned any valid memory address yet. b) To pass a null pointer to a function argument when we don’t want to pass any valid memory address.

Why void main is wrong?

You generally want to know the exit status of your program. That’s the reason why you have the int main() — you return your exit status. It’s wrong because this is not what the C++ Standard specifies as a legal main . Nobody cares about what the other languages specify.

What is printf () in C?

“printf” is the name of one of the main C output functions, and stands for “print formatted”. printf format strings are complementary to scanf format strings, which provide formatted input (parsing). … Many languages other than C copy the printf format string syntax closely or exactly in their own I/O functions.

What is the int main ()?

int main – ‘int main’ means that our function needs to return some integer at the end of the execution and we do so by returning 0 at the end of the program. 0 is the standard for the “successful execution of the program”. main – In C89, the unspecified return type defaults to int.

What can’t you 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 the size of generic pointer?

4 bytesWhat is size of generic pointer in C++ (in 32-bit platform)? Explanation: Size of any type of pointer is 4 bytes in 32-bit platforms.

Why dangling pointers are dangerous?

“If that piece of memory has been erased, and the pointer doesn’t know it has been erased, then you have a dangling pointer,” Allan said, noting that such dangling pointers can cause systems to become unstable or crash. …

What is a void * pointer?

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. A null pointer is a pointer that does not point to an address. A void pointer can be a null pointer.

What is generic pointer?

It make sense to have a pointer type that can hold the address of any data type. When a variable is declared as being a pointer to type void it is known as a generic pointer.

How do I print a void?

The %p formatting specifier is for void * . printf(“%p\n”, out); is the correct way to print a (void*) pointer.

What is the void data type?

Overview. The void data type, similar to the Nothing data type described earlier, is the data type for the result of a function that returns normally, but does not provide a result value to its caller.

Can a pointer be void?

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.

How do you identify a dangling pointer?

Detecting Dangling pointer to the stack During a call to p, x is set to point to the address of y, which is on the stack. After p returns, y is deallocated and x therefore becomes a dangling pointer in the stack.

What’s void in Java?

void is a Java keyword. Used at method declaration and definition to specify that the method does not return any type, the method returns void .

What is int main void?

main (void) mean? In C and C++ int main(void) means that the function takes NO arguments. C++ does the same even if you simply write int main() , which says the function does not take any argument, and if you dont put void in it, it’ll be the same, but in C there’s a little difference in int main() and int main(void) .

What is null and void pointer?

Null pointer is a special reserved value of a pointer. A pointer of any type has such a reserved value. … Void pointer is a specific pointer type – void * – a pointer that points to some data location in storage, which doesn’t have any specific type. So, once again, null pointer is a value, while void pointer is a type.

What is void * C++?

void (C++) When used in the declaration of a pointer, void specifies that the pointer is “universal.” If a pointer’s type is void*, the pointer can point to any variable that is not declared with the const or volatile keyword. A void* pointer cannot be dereferenced unless it is cast to another type.

What is null C?

Null is a built-in constant that has a value of zero. It is the same as the character 0 used to terminate strings in C. Null can also be the value of a pointer, which is the same as zero unless the CPU supports a special bit pattern for a null pointer.