...
In this noncompliant code example, the case where widget_type is WE_W lacks a break statement. Consequently, statements that should only be executed when widget_type is WE_X are executed even when widget_type is WE_W.
| Code Block | ||||
|---|---|---|---|---|
| ||||
enum WidgetEnum { WE_W, WE_X, WE_Y, WE_Z } widget_type;
widget_type = WE_X;
switch (widget_type) {
case WE_W:
/* ... */
case WE_X:
/* ... */
break;
case WE_Y:
case WE_Z:
/* ... */
break;
default: /* can't happen */
/* handle error condition */
}
|
...
In this compliant solution, each sequence of statements following a case label ends with a break statement.
| Code Block | ||||
|---|---|---|---|---|
| ||||
enum WidgetEnum { WE_W, WE_X, WE_Y, WE_Z } widget_type;
widget_type = WE_X;
switch (widget_type) {
case WE_W:
/* ... */
break;
case WE_X:
/* ... */
break;
case WE_Y:
case WE_Z:
/* ... */
break;
default: /* can't happen */
/* handle error condition */
}
|
...
MSC17-EX2: When control flow is intended to cross statement labels, it is permissible to omit the break statement. In these instances, the unusual control flow must be explicitly documented.
| Code Block | ||||
|---|---|---|---|---|
| ||||
enum WidgetEnum { WE_W, WE_X, WE_Y, WE_Z } widget_type;
widget_type = WE_X;
switch (widget_type) {
case WE_W:
/* ... */
/* no break, process case for WE_X as well */
case WE_X:
/* ... */
break;
case WE_Y: case WE_Z:
/* ... */
break;
default: /* can't happen */
/* handle error condition */
}
|
...