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2023-12-01

还有其他一些重要的运算符，包括sizeof和? : ? : Objective-C语言支持。

操作者	描述	例
sizeof()	返回变量的大小。	sizeof（a），其中a是整数，将返回4。
&	返回变量的地址。	＆一个; 将给出变量的实际地址。
*	Pointer to a variable.	*一个; 将指向变量。
？ :	条件表达式	如果条件为真？然后是值X:否则为Y值

例子 (Example)

尝试以下示例来了解Objective-C编程语言中可用的所有其他运算符 -

#import <Foundation/Foundation.h>
int main() {
   int a = 4;
   short b;
   double c;
   int* ptr;
   /* example of sizeof operator */
   NSLog(@"Line 1 - Size of variable a = %d\n", sizeof(a) );
   NSLog(@"Line 2 - Size of variable b = %d\n", sizeof(b) );
   NSLog(@"Line 3 - Size of variable c= %d\n", sizeof(c) );
   /* example of & and * operators */
   ptr = &a;	/* 'ptr' now contains the address of 'a'*/
   NSLog(@"value of a is  %d\n", a);
   NSLog(@"*ptr is %d.\n", *ptr);
   /* example of ternary operator */
   a = 10;
   b = (a == 1) ? 20: 30;
   NSLog(@"Value of b is %d\n", b );
   b = (a == 10) ? 20: 30;
   NSLog(@"Value of b is %d\n", b );
}

编译并执行上述程序时，会产生以下结果 -

2013-09-07 22:46:22.702 demo[24593] Line 1 - Size of variable a = 4
2013-09-07 22:46:22.703 demo[24593] Line 2 - Size of variable b = 2
2013-09-07 22:46:22.703 demo[24593] Line 3 - Size of variable c= 8
2013-09-07 22:46:22.703 demo[24593] value of a is  4
2013-09-07 22:46:22.703 demo[24593] *ptr is 4.
2013-09-07 22:46:22.703 demo[24593] Value of b is 30
2013-09-07 22:46:22.703 demo[24593] Value of b is 20