The switch structure

The switch structure can often be used in place of a cascade of if's.

Syntax

  switch (E) 
  {
      case C1 :
          statements_1;
          break;
      case C2 :
          statements_2;
          break;
      .
      .
      .
      default :
          statements_n;
          break;    
  }

E is the control expression which should evaluate to an integer.

the Ci's should be integer constants.

case C1: statements_1; break; is a case clause

default: statements_n; break; is a default clause

Semantics

E is evaluated
If E's value is equal to one of the Ci's, then control is immediately transfered to that case.
...Otherwise, if there is a default clause, control is transferred there.
......Otherwise, exit the switch.
The statements in that selected case are evaluated.
If a break is evaluated, control is transfered to the next statement after the switch

Good programming practice

include a break in every clause
always include a default clause

Wednesday, 16-Sep-1998 18:22:08 EDT