Jump table instead of Switch cases

[srikky]

Hi,

I have an issue with switch case. There are about 32 cases to be handled in switch. each case just assigns a hexadecimal to a local variable.

#define ADFV 0x0301

Switch(error_index)
{
case 1:
var = ADFV;
........

}
}
can i use jump table for above issue to reduce the code size.

[weaknessforcats]

You could if you wanted but the fact is that a 32 case switch statment is pretty small and the change in the size of your executable will be miniscule. I don't think it's worth the effort.

[srikky]

Thanks for your suggestion.

[srikky]

Is it a good practice to use those many switch cases... is there any other better approach?

[donbock]

Can you count on the error_index values all being roughly between 0 and some maximum value -- with very few holes from unused error_index values? If so, then you could use a lookup table where each entry consists of a var value. Use error_index to index into the lookup table array.

If error_index is not appropriate for use as an array index, then you could construct a lookup table where each entry has two fields: error_index and corresponding var. You could then replace the switch with a search-the-table snippet.