_c language based on a macro definition containing if in C

Macro definition that contains if
When the macro definition contains an IF
1) define the following macros
#define DC (P) if (foo (p)) fun (p)
Used in the following environment
if (k>n)
DC (k);
Else
DC (n);
After the macro is replaced, the following
if (k>n)
if (foo (k))
Fun (k);
Else
if (foo (n))
Fun (n);
Visible, the original if and else are no longer paired.
2 To avoid such problems, we can define a macro that contains an if statement as a whole.
#define DC (P) {if (P)) fun (p);}
However, replace and then become
if (k>n)
{
if (foo (k))
Fun (k);
};else ...
If you have a semicolon in front of else, you are prompted at compile time that the error is not paired with else.
3 For these reasons, in the macro definition, the statement sequence is often placed in the do{...} while (0) block.
As follows
#define DC (P) do{(if (foo (p)) fun (p); while (0)
After replacement
if (k>n)
Todo
{
if (foo (k))
Fun (k);
}while (0);
Else
...
Programs can run correctly
4) Replacement scheme
A) adopted? : An expression
#define DC (P) (foo (p))? (Fun (P)): 0)
( b) using the short path evaluation attribute of Boolean operation
#define DC (P) ((foo (p)) && (Fun (p), 1)
Reference books: << code reading methods and practices >>