Objective-C 中的关系运算符

下表列出了 Objective-C 语言支持的所有关系运算符。假设变量A为 10，变量B为 20，则 -

操作员	描述	例子
==	检查两个操作数的值是否相等；如果是，则条件成立。	(A == B) 不正确。
!=	检查两个操作数的值是否相等；如果值不相等，则条件为真。	(A != B) 为真。
>	检查左操作数的值是否大于右操作数的值；如果是，则条件成立。	(A > B) 不正确。
<	检查左操作数的值是否小于右操作数的值；如果是，则条件成立。	(A < B) 为真。
>=	检查左操作数的值是否大于或等于右操作数的值；如果是，则条件成立。	(A >= B) 不正确。
<=	检查左操作数的值是否小于或等于右操作数的值；如果是，则条件成立。	(A <= B) 为真。

例子

尝试以下示例来了解 Objective-C 编程语言中可用的所有关系运算符 -

现场演示

#import <Foundation/Foundation.h>

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

   if( a == b ) {
      NSLog(@"Line 1 - a is equal to b\n" );
   } else {
      NSLog(@"Line 1 - a is not equal to b\n" );
   }
   
   if ( a < b ) {
      NSLog(@"Line 2 - a is less than b\n" );
   } else {
      NSLog(@"Line 2 - a is not less than b\n" );
   } 
   
   if ( a > b ) {
      NSLog(@"Line 3 - a is greater than b\n" );
   } else {
      NSLog(@"Line 3 - a is not greater than b\n" );
   }
   
   /* 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\n" );
   }
   
   if ( b >= a ) {
      NSLog(@"Line 5 - b is either greater than  or equal to b\n" );
   }
}

当您编译并执行上述程序时，它会产生以下结果 -

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

Objective_c_operators.htm