Give explanation to this question

Question

#define square(x) x*x
Printf("%d",square(4+1));

Answer 1

Notice that wrapping parenthesis may eliminate the problem but it wouldn't be a remedy for undefined behavior caused by increment/decrement operator like so

int a = 4;
printf("%d", square(++a)); // UB

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https://en.wikipedia.org/wiki/Undefined_behavior#Examples_in_C_and_C++

Answer 2

You're defining a macro/preprocessor directive that will replace every occurrence of "square(x)" in the source code with "x*x" before the code is compiled.

Unfortunately, this will lead to wrong/unexpected results because it will replace "square(4+1)" with "4+1*4+1", which is 9, instead of 25.

To avoid that, you can use #define square(x) (x)*(x) instead: square(4+1) => (4+1)*(4+1) = 25.

Answer 3

Answer 25 or 9