NSString *type = @"hello";

    NSString *subtype = @"good";

    NSString *typesub = [NSString stringWithFormat:@"%@>%@",type,subtype];

    NSString *typesub1 = [type stringByAppendingString:subtype];

    NSString *typesub2 = [type stringByAppendingFormat:@"%@>%@",type,subtype];

    NSString *a= @"abc" ;

    NSString *typesub3 = [type stringByAppendingFormat:@"%@>%@>%@" ,type,subtype,a];

    NSLog(@"%@,%@,%@,%@",typesub,typesub1,typesub2,typesub3,typesub3);