ios - How to validate fractional number -

i trying write function returns boolean value if given string in valid fractional format or not.

e. g. fraction numbers follows 2/3, 1 2/3, 6/5, 80/20, 60 1/4, etc.

-(bool)validatefraction:(nsstring *)string {   if(string valid fraction)     return yes;   else      return no; } 

you can use regular expressions that:

-(bool)validatefraction:(nsstring *)string{     nsstring *fractionregex = @"\\d+(/\\d+)?";     nspredicate *fractiontest = [nspredicate predicatewithformat:@"self matches %@", fractionregex];     return [fractiontest evaluatewithobject:string]; } 

p.s. not also, that function not validate against division 0 , not allow fraction have sign (+ or -) @ front