Question #24 in the otherwise quite reasonable C/C++ programming quiz at Cprogramming.com is as follows:
C is to C++ as 1 is to
a) What the heck?
b) 2
c) 10
I think I have a new favourite interview question.
Anyway, have a guess what they give as an answer.
That’s right, b).
Apparently they think C is almost a strict subset of C++, in exactly the same way that 1 is almost a strict subset of 2.
It seems perfectly clear to me. You just need to go back to definitions.
What is C++? The Jargon File defines it as “Designed by Bjarne Stroustrup of AT&T Bell Labs as a successor to C. ”
What is the number 2? Peano defined it as the successor to 1.
Ergo, Cis to C++ as 1 is to 2.
Q.E.D.
Do I get the job?
Nicely done, except it probably should be the other way around. C99 is the most recent standardisation of C, dating back to 1999 (obviously). C++ was ratified as a standard in 1998.
Hence, C : C++ :: 2 : 1
And don’t call us, we’ll call you.
I think you just treat C as a regular variable, which means the expression C++ evaluates to 2. (You would of course soundly thrash any programmer who defined a variable using a capital letter.)
By this incremental reasoning, answer (c) is also correct, since any computer geek worth hiring looks at “10” and says “two.”
No it doesn’t! If C is 1, then C++ evaluates to 1 also. ++C evaluates to 2.
I’m sorry, the position has been filled!
I agree that in the expression “C++,” if C is referenced, it returns the value 1 before incrementing C. But the entire expression evaluates to 2; else the following would never end:
for (C=1; C<=10; C++) { … }
Another way to say it: What’s the output of this?
int main() { int C = 1; while (C++ < 3) { printf(“%d\n”, C); } return 0; }
I’d take a leaf from the new series of Doctor Who, where they occasionally travel to the year five billion when numbers are augmented by other symbols – so the episode The End Of The World happens in the year 5.5/Apple/26. So I’d say that C++ is a partial superset of C with some incompatibilities, and therefore C is to C++ as 1 is to 1.943turnip7442gorilla04.
Do I win?
Sorry folks, but unlike you nerds, computers think in BINARY, not decimal. The binary representation for what you call “2” is “10”. So the correct answer is c) “10”.