switch statement programming
(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)) printf("Hellon"); /* fall through */ case 2: printf("Goodbyen"); break; case 3: printf("Fishn"); break; default: fprintf(stderr, "Odd foo valuen"); 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)