Using a range of numbers in switch structure

If you have consecutive ranges, the most robust approach is to "step down the stairs" instead of giving ranges which might end up in subtle mistakes. E.g. assuming you have the ranges ...0, 1...999, 1000...1999, 2000..., a possible solution might be from top-down:

if (n >= 2000) {
  // 2000...
} else if (n >= 1000) {
  // 1000...1999
} else if (n >= 1) {
  // 1...999
} else {
  // ...0
}

[EDIT]
Now that you mention your instructor wants switch (e.g. for didactic reason), you might calculate a range indicator and use that in the switch. E.g.

int lower_bound = n >= 2000 ? 2000
                : n >= 1000 ? 1000
                : n >=    1 ?    1
                : 0
                ;
switch(lower_bound)
{
case 2000:
  // 2000...
  break;
case 1000:
  // 1000...1999
  break;
case 1:
  // 1...999
  break;
default:
  assert(!"out-of-range");
  break;
}

[/EDIT]

Regards
Andi

If your instructor really really wants a switch, then create something like:

int switchVal;
if(n<1)
  switchVal= 1;
if(n>1 && n<100)
  switchVal= 2;
... 
etc.

Now you can use

switch(switchVal) {
  case 1: whatever;
         break;
   (more etc.)     
} 

and make him/her happy.

this is no task for a switch, but the if/else commands

if( n >= 1|| n <= 999 ) {
} else if( n >= 1000|| n <= 1999 ) {
} else if( n >= 2000 ) {
} 

watch out for the ">=" equalities.

I think that in Swift from Apple you can write stuff like this

switch( n ) {
  case 1...999:
    break;
}