Is
a default case necessary in a switch statement?
Answer:
No,
but it is not a bad idea to put default statements
in switch statements for error- or logic-checking purposes. For instance,
the following switch statement is perfectly normal:
switch
(char_code)
{
case ‘Y’:
case ‘y’:
printf(“You answered YES!\n”);
break;
case ‘N’:
case ‘n’:
printf(“You answered NO!\n”);
break;
}
Consider,
however, what would happen if an unknown character code were passed to this switch statement.
The
program would not print anything. It would be a good idea, therefore, to insert
a default case where this condition would be taken care of:
...
default:
printf(“Unknown response: %d\n”, char_code);
break;
...
Additionally,
default cases come in handy for logic checking. For instance, if your switch statement
handled a fixed number of conditions and you considered any value outside those
conditions to be a logic error, you could insert a default case which would
flag that condition. Consider the following example:
void
move_cursor(int direction)
{
switch
(direction)
{
case UP:
cursor_up();
break;
case
DOWN: cursor_down();
break;
case
LEFT: cursor_left();
break;
case
RIGHT: cursor_right();
break;
default:
printf(“Logic error on line number %ld!!!\n”,__LINE__);
break;
}
}
Cross
Reference:
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Posted By Sundeep aka SunTechie
Sundeep is a Founder of Youth Talent Auzzar, a passionate blogger, a programmer, a developer, CISE and these days he is pursuing his graduation in Engineering with Computer Science dept.
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