Q. Consider the following C declaration.
int x[10], y,z;
What kind of error does following statement contain?
z == x +y;
a. Syntax error
b. Semantic error
c. logical error
d. All of the above
According to me it should be option a, but I am confused, can anybody get confirm answer with explanation.
Thanks a lot for your replies
Why do you think there is a syntax error?
Look up a C++ Reference and learn How To Ask Questions The Smart WayOriginally Posted by Bjarne Stroustrup (2000-10-14)
because x is declared as array and z is not so
But syntax can be correct and meaningless at the same time. Observe it in English: "The flow of quizzes revels in authority." (Nonsense generator) The meaning of the statement is the problem.
so what should be the answer according to you
Yeah, but that is somewhat incomplete. Go further: the left hand side expression of the == is of type int. The right hand side expression is of type int*, since the array is converted to an int*, then when you add the int to that, the resulting expression is still an int*. Hence, this compares an int with an int*.
The thing is, syntactically, the statement is valid. We can refer to the syntax from Clause 6.5.9 of C99:
I do not want to delve too deeply into this, so take my word that both z and x + y are relational expressions.Code:equality-expression: relational-expression equality-expression == relational-expression
The operand types provide semantic information; they give meaning to the expressions (e.g., "we're comparing two pointers"), and when we look at the constraints on operator==
We see that actually the expression has no meaning because the types of the operands of operator== violates the constraints required to interpret it. Therefore, there is a semantic error.
It may be possible to argue that there is also a logical error because the author presumably intended some logic that did not happen because of the semantic error.
Look up a C++ Reference and learn How To Ask Questions The Smart Way
Thanks for such a good explanation
yes I am also confused about logical error, so finally what should be the answer SEMANTIC or LOGICAL
Well, the program might still compile but produce a wrong result (but note that as given, the snippet has no net effect). However, I believe that a compiler could reject the program. So, what answer would you pick?
Look up a C++ Reference and learn How To Ask Questions The Smart Way
may be syntax or semantic, because complier would reject if syntax is not correct, what do you say
Gah! The point is for you to take what you have learned, analyze and decide for yourself. You have been given enough info to eliminate two of the 3 types of errors. If you are trying to decide between syntax and semantic, reread laserlight's post #6 very carefully.
I had read it carefully before according to that answer is SEMANTIC error
Good. I agree with your conclusion.
