switch statement

Technology Dictionary -> switch statement

switch statement



(Or case statement, multi-way branch) A construct found in most high-level languages for selecting one of several possible blocks of code or branch destinations depending on the value of an expression. An example in C is

switch (foo(x, y)) case 1: printf("Hello "); /* fall through */ case 2: printf("Goodbye "); break; case 3: printf("Fish "); break; default: fprintf(stderr, "Odd foo value "); exit(1);

The break statements cause execution to continue after the whole switch statemetnt. The lack of a break statement after the first case means that execution will fall through into the second case. Since this is a common programming error you should add a comment if it is intentional.

If none of the explicit cases matches the expression value then the (optional) default case is taken.

A similar construct in some functional languages returns the value of one of several expressions selected according to the value of the first expression. A distant relation to the modern switch statement is Fortran's computed goto.

(1997-01-30)


© Art Branch Inc.

SQL Tutorial