Question

Instead of using else if like this

            if([screen isEqualToString :@"A"]){

               }
             else if(screen isEqualToString:@"B"){

               }

Will it work like this

          switch ([string isEqualToString:screen]){
          case ISA:
          break;

          case ISB:
          break;

          default:
          break;
       }

where ISA and ISB is defined like

       #define ISA [screen isEqualToString:A] and **will it be efficient**

Answer 1

No, I most certainly don’t think so. switch/case is all about numeric if/then/else cases.

However what you COULD do is the following:

Write a function and pass it a variable number of arguments (since objective-c implements C look up va_args for the syntax). Pass it the original string and the strings you want to compare to.

Inside that function, use a ‘for’ loop, which compares the strings one by one until it either reaches the end or finds a match according to your criteria.

Once either is met, return the index. And that index you can use in switch case.
A little example:

switch([self compareStrings:@"FirstString" Options:"@FirstString", @"SecondString"]) {
    case 0: //FirstString
    break;

    case 1: //SecondString
    break;

    default: //Not found
    break;
}

That should work. Regarding your function: Be sure to either incorporate an Optioncount, or make the options ‘nil’ terminated, because otherwise the function won’t know when the end is actually reached.