macOS changing characters in string

[saurabh1jadhav]

i have a NSString *Str=@"macintosh". i want that 4th character should be in 2nd place and 2nd character in 4th place.(i.e. manctosh). How to do this??

 

[GorillaPaws]

You need to use an NSMutableString.

 

[jared_kipe]

Obviously you need the computer to do it for you because you cannot, (i.e. your example removes the letter i, but doesn't move it or the a).

-(NSString *) secondToFourth: (NSString *) inputString {
     if ([inputString length] < 4) {
          return nil;
     }

     NSMutableString *workingString = [NSMutableString stringWithString: inputString];
     NSRange secondPos = NSMakeRange( 1 , 1 );
     NSRange fourthPos = NSMakeRange( 3 , 1 );

     NSString *secondSub = [inputString substringWithRange: secondPos];
     NSString *fourthSub = [inputString substringWithRange: fourthPos];

     [workingString replaceCharactersInRange: fourthPos withString: secondSub];
     [workingString replaceCharactersInRange: secondPos withString: fourthSub];

     // all objects are autoreleased, including the returned one
     // this may not work on wider text encodings ;) but I don't care
     return workingString;
}

EDIT: added some exception checking