下表列出了所有支持Objective-C語言的關係運算符。假設變量A=10和變量B=20，則：

運算符	描述	示例
==	檢查是否兩個操作數的值等於或不等於，如果是的話那麼條件為真。	(A == B) is not true.
!=	檢查兩個操作數的值等於或不相等，如果值不相等，則條件為真。	(A != B) is true.
>	檢查是否左操作數的值大於右操作數的值，如果是的話那麼條件為真。	(A > B) is not true.
<	檢查是否左操作數的值小於右操作數的值，如果是的話那麼條件為真。	(A < B) is true.
>=	檢查是否左操作數的值大於或等於右操作數的值，如果是的話那麼條件為真。	(A >= B) is not true.
<=	檢查是否左操作數的值小於或等於右邊的操作數的值，如果是的話那麼條件為真。	(A <= B) is true.

例子

嘗試下麵的例子就明白了在Objective-C編程語言的所有關係運算符：

#import <Foundation/Foundation.h>

main()
{
   int a = 21;
   int b = 10;
   int c ;

   if( a == b )
   {
      NSLog(@"Line 1 - a is equal to b
" );
   }
   else
   {
      NSLog(@"Line 1 - a is not equal to b
" );
   }
   if ( a < b )
   {
      NSLog(@"Line 2 - a is less than b
" );
   }
   else
   {
      NSLog(@"Line 2 - a is not less than b
" );
   }
   if ( a > b )
   {
      NSLog(@"Line 3 - a is greater than b
" );
   }
   else
   {
      NSLog(@"Line 3 - a is not greater than b
" );
   }
   /* Lets change value of a and b */
   a = 5;
   b = 20;
   if ( a <= b )
   {
      NSLog(@"Line 4 - a is either less than or equal to  b
" );
   }
   if ( b >= a )
   {
      NSLog(@"Line 5 - b is either greater than  or equal to b
" );
   }
}

當編譯和執行上述程序，它會產生以下結果：

2013-09-07 22:42:18.254 demo[9486] Line 1 - a is not equal to b
2013-09-07 22:42:18.254 demo[9486] Line 2 - a is not less than b
2013-09-07 22:42:18.254 demo[9486] Line 3 - a is greater than b
2013-09-07 22:42:18.254 demo[9486] Line 4 - a is either less than or equal to  b
2013-09-07 22:42:18.254 demo[9486] Line 5 - b is either greater than  or equal to b