Without all the elses, the if's after the successful test will continue to
run. That is, every test will be run every time. With the elses, tests
after the success will be skipped. Another way to do this, which is, I
believe, more readable, is to use the switch-case statement.

I am surprised that you are testing for 10 specific ADC values. It is
unlikey that successive ADC readings will land on exactly a particular
number. More likely they will be one count higher or lower, perhaps more
variation depending on circuit stability. Do yo want to test the ADC for a
range of values? If so, the if, or if else if test seem to be he only way
to go (or a very large switch-case statement or a large array where the
ADC indexes into it).

Harold


> Hi to all engineers,
>
> I am reading ADC to compare 10 different values  if they are matched
> then each match
> has it's own set value. my question is.
>
> 1. what is the different between  if else if  for example
>
>     if (adc_x==1023)        // 5v         1023
>             {
>             xbyte_lsb=0xff ;
>             xbyte_msb=0x01 ;
>             }
>             else if (adc_x==921)   // 4,5v       921
>             {
>             xbyte_lsb=0x9A ;
>             xbyte_msb=0x01 ;
>             }
>
> or  without else if
>
>     if (adc_x==1023)        // 5v         1023
>             {
>             xbyte_lsb=0xff ;
>             xbyte_msb=0x01 ;
>             }
>             if (adc_x==921)   // 4,5v       921
>             {
>             xbyte_lsb=0x9A ;
>             xbyte_msb=0x01 ;
>             }
>
> I do not clearly understand what does "else if"  do?
>
> is there better way of testing ADC ?
>
> Any feedback will appreciate.
>
> Andre
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