Show 例子
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
