大小写字母转换

• (void)viewDidLoad
  {
  NSString *a = @"i like long dress";
  NSLog(@" \n 大写 a:%@ ", [a uppercaseString]);
  NSLog(@" \n 小写 a:%@ ", [a lowercaseString]);
  NSLog(@" \n 字母开头大写 a:%@ ", [a capitalizedString]);
  }

2011-07-11 17:33:58.082 Q[6111:207] **** ****大写 **a:I LIKE LONG DRESS **
2011-07-11 17:33:58.083 Q[6111:207] ****小写 **a:i like long dress **
2011-07-11 17:33:58.084 Q[6111:207] **** ****字母开头大写 a:I Like Long Dress