鍍金池/ 教程/ C/ Objective-C 關(guān)系運(yùn)算符
Objective-C 多態(tài)性
Objective-C 預(yù)處理器
Objective-C for循環(huán)
Objective-C 開發(fā)環(huán)境（安裝配置）
Obj-C Foundation/基礎(chǔ)框架
Objective-C 指針運(yùn)算
Objective-C 循環(huán)
Objective-C 錯誤處理
Objective-C while循環(huán)
Objective-C if語句
Objective-C do...while循環(huán)
Objective-C教程
Objective-C 嵌套switch語句
Objective-C 函數(shù)按值調(diào)用
Objective-C 常量
Objective-C 運(yùn)算符
Objective-C 數(shù)據(jù)類型
Objective-C 邏輯運(yùn)算符
Objective-C 數(shù)組作為函數(shù)參數(shù)傳遞
Objective-C struct/結(jié)構(gòu)
Objective-C 嵌套循環(huán)
Objective-C 函數(shù)引用調(diào)用
Objective-C 日志處理
Objective-C 數(shù)據(jù)存儲
Objective-C 教程首頁
Objective-C 擴(kuò)展
Objective-C 異常處理
Objective-C 類型轉(zhuǎn)換
Objective-C 嵌套 if 語句
Objective-C typedef
Objective-C 決策
Objective-C 指針的數(shù)組
Objective-C Protocols/協(xié)議
Objective-C 日期和時間
Objective-C 指針
Objective-C 內(nèi)存管理
命令行參數(shù)
Objective-C NSString/字符串
Objective-C 動態(tài)綁定
Objective-C 復(fù)合對象
Objective-C Arrays/數(shù)組
Objective-C 位運(yùn)算符
Objective-C 指向指針的指針
Objective-C 從函數(shù)返回數(shù)組
Objective-C Posing/冒充
Objective-C Categories/類別
Objective-C 文件處理
Objective-C 賦值運(yùn)算符
Objective-C 函數(shù)返回指針
Objective-C if...else 語句
Objective-C switch語句
Objective-C URL加載系統(tǒng)
Objective-C 算術(shù)運(yùn)算符
Objective-C Numbers/數(shù)字
Objective-C語言程序結(jié)構(gòu)
Objective-C 快速枚舉
Objective-C 基本語法
Objective-C 類&對象
Objective-C 變量
Objective-C 關(guān)系運(yùn)算符
Objective-C 塊
Objective-C break語句
Objective-C continue語句
Objective-C 語言概述
Objective C 文本和字符串
Objective-C 函數(shù)
Objective-C 傳遞函數(shù)的指針
Objective-C 數(shù)組的指針
Objective-C 多維數(shù)組
Objective-C 繼承
Objective-C 數(shù)據(jù)封裝

Objective-C 關(guān)系運(yùn)算符

下表列出了所有支持Objective-C語言的關(guān)系運(yùn)算符。假設(shè)變量A=10和變量B=20，則：

運(yùn)算符 描述 示例
== 檢查是否兩個操作數(shù)的值等于或不等于，如果是的話那么條件為真。 (A == B) is not true.
!= 檢查兩個操作數(shù)的值等于或不相等，如果值不相等，則條件為真。 (A != B) is true.
> 檢查是否左操作數(shù)的值大于右操作數(shù)的值，如果是的話那么條件為真。 (A > B) is not true.
< 檢查是否左操作數(shù)的值小于右操作數(shù)的值，如果是的話那么條件為真。 (A < B) is true.
>= 檢查是否左操作數(shù)的值大于或等于右操作數(shù)的值，如果是的話那么條件為真。 (A >= B) is not true.
<= 檢查是否左操作數(shù)的值小于或等于右邊的操作數(shù)的值，如果是的話那么條件為真。 (A <= B) is true.

例子

嘗試下面的例子就明白了在Objective-C編程語言的所有關(guān)系運(yùn)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(dāng)編譯和執(zhí)行上述程序，它會產(chǎn)生以下結(jié)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

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