Objective-C sizeof和三元运算符

Objective-C中还有其他一些重要的运算符，包括sizeof和?:三元运算符，Objective-C语言也都支持。

例子

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 );
}

执行上面示例代码，得到以下结果：

2018-11-14 05:18:49.270 main[174436] Line 1 - Size of variable a = 4
2018-11-14 05:18:49.271 main[174436] Line 2 - Size of variable b = 2
2018-11-14 05:18:49.271 main[174436] Line 3 - Size of variable c= 8
2018-11-14 05:18:49.271 main[174436] value of a is  4
2018-11-14 05:18:49.271 main[174436] *ptr is 4.
2018-11-14 05:18:49.272 main[174436] Value of b is 30
2018-11-14 05:18:49.272 main[174436] Value of b is 20