C++

8.2    The Empty Statement

When you write a semicolon where a statement is expected, that is an empty statement. This statement does nothing.

int main() {  ;;;                 // 3 empty statements    int number = 12 ; ;           // 1 empty statement    ; int q = number*number ;     // 1 empty statement    if(q>50) {        q = q - 50;    } ;                           // 1 empty statement    std::cout << q << std::endl;}  

Listing 8.7     Empty statements everywhere.

Doing nothing is usually completely uncritical. However, there are cases where an inserted empty statement is dangerous. You already know from Chapter 4 that an if is followed by a statement that should be executed if a condition is met. Suppose you insert an empty statement after if(q>50) in the preceding example:

    if(q>50) ;  {               // empty statement with serious ...