sizeof(blank class) == 1. why? [duplicate]

This question already has answers here: 开发者_如何学编程 Closed 12 years ago.

Possible Duplicate:

C++: What is the size of an object of an empty class?

#include <iostream>

class C
{
};

int main()
{
    std::cout << sizeof(C) << std::endl;

    return 0;
}

output: 1

Why 1, but not zero ?

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From Stroustrup's mouth sizeof. To ensure that the addresses of two different objects will be different. For the same reason, "new" always returns pointers to distinct objects.

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Because the C++ standard requires all objects to have a nonzero size. This helps ensure that every object has a unique address.

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The c++ standard says that every class/struct must have at least 1 byte.