Use of null statement in C

Question

What are typical uses of null statement

;

in C ?

I know that it is basically used to skip expression where it is expected

Answer 1

The only uses I can think of are:

1- At the end of a loop, where the operations are already encoded within the loop statements. e.g. while(a[i--]);

2- At the end of a label, where no operation is needed to be done. e.g. Label: ;

Answer 2

It's more of a null expression rather than a null statement, but it's often found in for loops.

for (;;)                 // Loop "forever"

for (int i=10; i--; )    // 9..0

etc

Answer 3

i was wondering how to write a null expression into the inline if and came up with this. it compiles and works.

condition ? x = 1 : "do nothing";

fun stuff.

Answer 4

while (somethingWithSideEffects()) ;

Answer 5

It's typically the side-effect of a code block that was stripped by the preprocessor, like

#if DEBUG
    #define ASSERT(_x) Assert(_x)
#else
    #define ASSERT(_x)
#endif


ASSERT(test);    // Results in null statement in non-debug builds

That, or in loops where your condition already contains whatever needs to be done in each iteration.

Answer 6

Example:

 while (!kbhit())
     ;

Should be self-explanatory.