Objective-C程序设计 CH6.4

Code: (Objective-C)

1. int main(int argc, const char * argv[])  
2. {  
3.       
4.     @autoreleasepool {  
5.         double  value;  
6.         char    operator;  
7.                   
8.         Calculator *deskCalc = [[Calculator alloc] init];  
9.           
10.         printf("**********Simple Printing Calculator**********\n");  
11.         printf("Mathematical operators supported: +  -  *  /\n");  
12.         printf("Utility operators:  S = set accumulator     E = Exit\n\n");  
13.           
14.         NSLog(@"Type in your expression.  Format: VALUE  EXPRESSION");  
15.   
16.         while (operator != 'E')  
17.         {  
18.             scanf("%lf %c", &value, &operator );  
19.             switch (operator)  
20.             {  
21.                 case '+':  
22.                     [deskCalc add: value];  
23.                     break;  
24.                 case '-':  
25.                     [deskCalc subtract: value];  
26.                     break;  
27.                 case '*':  
28.                     [deskCalc multiply: value];  
29.                     break;  
30.                 case '/':  
31.                     if (value == 0)  
32.                         NSLog (@"NAN, please choose a non-zero value");  
33.                     else  
34.                         [deskCalc divide: value];  
35.                         break;  
36.                 case 'S':  
37.                     [deskCalc setAccumulator: value];  
38.                     break;  
39.                 case 'E':  
40.                     NSLog(@"Exit");  
41.                     break;  
42.                 default:  
43.                     NSLog (@"Unknown operator; please choose a valid operator: + - * /");  
44.             }  
45.             NSLog (@"= %.3f", [deskCalc accumulator]);  
46.          }  
47.     }  
48.     return 0;  
49. }