Table of Contents
Why sizeof empty struct is 0 in C?
The C++ standard does not permit objects (or classes) of size 0. This is because that would make it possible for two distinct objects to have the same memory location. This is the reason behind the concept that even an empty class and structure must have a size of at least 1.
What is the size of an empty structure in C?
1 byte
Sizeof empty struct is 0 byte in C but in C++ it is 1 byte.
Can we define empty structure in C?
Empty struct in C is undefined behaviour (refer C17 spec, section 6.7. If the struct-declaration-list does not contain any named members, either directly or via an anonymous structure or anonymous union, the behavior is undefined.
Can a struct be empty?
An empty struct is a struct type without fields struct{} . The cool thing about an empty structure is that it occupies zero bytes of storage. The size of a struct is the sum of the size of the types of its fields, since there are no fields: no size!
Why is the size of an empty structure 1 byte?
Behaviour of that object is also nothing, but compiler assigns a unique address to that object. Memory in Computer is always organized in the form of bytes and minimum memory available at object address location is 1 byte. That’s why size of object of empty class is 1 byte.
Why is the size of empty Class 1 byte?
Why actually an empty class in C++ takes one byte? Simply a class without an object requires no space allocated to it. The space is allocated when the class is instantiated, so 1 byte is allocated by the compiler to an object of an empty class for its unique address identification.
What is an empty structure?
The empty struct is a struct type that has no fields. Here are a few examples in named and anonymous forms type Q struct{} var q struct{}
What is size of empty class?
The size of an empty class is not zero. It is 1 byte generally. It is nonzero to ensure that the two different objects will have different addresses.
Why is the size of an empty class?
Actually, the standard does not permit objects (or classes) of size 0, this is because that would make it possible for two distinct objects to have the same memory location. This is the reason behind the concept that even an empty class must have a size at least 1. It is known that size of an empty class is not zero.
Why is size of empty class is not zero?
The size of an empty class is not zero. It is 1 byte generally. It is nonzero to ensure that the two different objects will have different addresses.
What is the size of an empty class or class with only normal functions?
Bjarne Stroustrup talks about this too. Class without any data members and member function such type of class is known as empty class. Size of object of empty class is always 1 byte.
What is the size of an empty struct in C++?
Sizeof empty struct is 0 byte in C but in C++ it is 1 byte.
Is it possible to have an empty structure in C?
You cannot have an empty structure in C. It is a syntactic constraint violation. However gcc permits an empty structure in C as an extension . Furthermore the behaviour is undefined if the structure does not have any named member because If the struct-declaration-list contains no named members, the behavior is undefined.
What is the size of an empty class and structure?
This is because that would make it possible for two distinct objects to have the same memory location. This is the reason behind the concept that even an empty class and structure must have a size of at least 1. It is known that the size of an empty class is not zero. Generally, it is 1 byte.
What is the minimum size of a structure in C/C++?
Generally, it is 1 byte. The C++ Structures also follow the same principle as the C++ Classes follow, i.e. that structures in c++ will also not be of zero bytes. The minimum size must be one byte. Creating an empty structure in C/C++ is a syntactic constraint violation. However, GCC permits an empty structure in C as an extension.
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