Can a while statement end in a semicolon?

Answer 1

Yes. A while statement ends in a statement...

while (expression) statement

...and that statement can be a null statement, a single statement, or a block of statements. In the case of the block of statements, there is also a set of braces surrounding them...

while (expression);

while (expression) statement;

while (expression) {

statement1;

statement2;

...

statementN;

}

In the case where the body of the statement is null, there is no body. This is often done while taking advantage of side effects. For instance, to copy a string you could use...

char *strcpy (char *pszDestination, char *pszSource) {

char *pszTemp = pszDestination;

while ((*pszDestination++ = *pszSource++) != '\0');

return pszTemp;

}

...this works because the post-increment (++) operator has higher precedence than the dereference (*) operator, and because the assignment (=) operator has the value of the assignment, which is compared using the not equal (!=) operator against the string terminator null.

Note, carefully, the inner parentheses. They are needed because != has higher precedence than =, and you want it the other way around. Also, some compilers will let you eliminate the != '\0' terms and the inner parentheses, but that is not portable, and most compilers will warn you about assignment in a conditional expression.

In the case of a single statement you could use...

i= -1;

while (++i < argc) printf ("%d %s\n", i, argv[i]);

...here the while statement also ends in a semicolon.

The case of the block of statements is not shown, because it seems to be understood from the context of the question.