Different output in C and C++ with sizeof operator

Question

Why does this code produces different o/p in C and C++?

int i = sizeof('a');

Answer 1

In C, the type of a character constant like 'a' is actually an int, with size of 4 (or some other implementation-dependent value). In C++, the type is char, with size of 1. This is one of many small differences between the two languages.

Answer 2

Character literals in C are ints, whereas in C++ they are chars. In any case sizeof(char) is always 1 by definition.

Answer 3

This is because C and C++ define character literals differently. In C, character literals are treated as int while in C++ they are treated as char.