1 /*
 2  计算器类
 3  1>返回π
 4  2>计算两个整数的平方
 5  3>计算两个整数的和
 6  */
 7 
 8 
 9 #import <Foundation/Foundation.h>
10 
11 @interface Calculator: NSObject
12 //方法名:pi
13 - (double) pi;
14 
15 //OC方法中，一个参数对应一个冒号:
16 //方法名：squr:
17 - (int) squr:(int) num;
18 
19 //方法名: sumWithNum1:andNum2:
20 - (int) sumWithNum1:(int)num1 andNum2:(int)num2;
21 
22 @end
23 
24 
25 @implementation Calculator
26 - (double) pi
27 {
28     return 3.14;
29 }
30 
31 - (int) squr: (int) num
32 {
33     return num * num;
34 }
35 
36 - (int) sumWithNum1:(int)num1 andNum2:(int)num2;
37 {
38     return num1 + num2;
39 }
40 @end
41 
42 
43 int main()
44 {
45     Calculator *c = [Calculator new];
46     int d1 = 4;
47     int d2 = 5;
48     int d3 = 9;
49     NSLog(@"PI = %f", [c pi]);
50     NSLog(@"%d 的平方是 %d",d1, [c squr: d1]);
51     NSLog(@"%d + %d = %d", d2, d3, [c sumWithNum1:d1 andNum2:d3]);
52     return 0;
53 }