[Objective-c 基础 - 1.3] OC带返回值的类方法

 /*
  计算器类
  1>返回π
  2>计算两个整数的平方
  3>计算两个整数的和
  */

 #import <Foundation/Foundation.h>

 @interface Calculator: NSObject
 //方法名:pi
 - (double) pi;

 //OC方法中，一个参数对应一个冒号:
 //方法名：squr:
 - (int) squr:(int) num;

 //方法名: sumWithNum1:andNum2:
 - (int) sumWithNum1:(int)num1 andNum2:(int)num2;

 @end

 @implementation Calculator
 - (double) pi
 {
     return 3.14;
 }

 - (int) squr: (int) num
 {
     return num * num;
 }

 - (int) sumWithNum1:(int)num1 andNum2:(int)num2;
 {
     return num1 + num2;
 }
 @end

 int main()
 {
     Calculator *c = [Calculator new];
     int d1 = ;
     int d2 = ;
     int d3 = ;
     NSLog(@"PI = %f", [c pi]);
     NSLog(@"%d 的平方是 %d",d1, [c squr: d1]);
     NSLog(@"%d + %d = %d", d2, d3, [c sumWithNum1:d1 andNum2:d3]);
     return ;
 }