2. What will be the result of:

int f(int a) { return ++a; }
int f(unsigned int a) { return --a; }
cout << f(5);

A. Undefined behaviour

B. I don't know

C. Compiler error

D. 6

E. 5

F. 4

 

any body know what is the answer? i think it is D right?

 

D is indeed the correct answer.

The web page located at http://cpp.comsci.us/etymology/literals.html describes the various literals that are allowed in C/C++ to describe the various data types. A number on its own is considered an int, and as such the first function list will be executed as it is the closest match for the variable type.

If the author had put 5U it would have become an unsigned integer and the program would have output an unsigned int 4.

 

thanks X-Istence

 

sure
the answer is 6