完整代码示例

#import   
   @interface TemperatureConverter : NSObject  
  - (double)celsiusToFahrenheit:(double)celsiusTemperature;  
  - (double)fahrenheitToCelsius:(double)fahrenheitTemperature);  
  @end  
  int main(int argc, char **argv) {  
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];  
    // 检查命令行参数  
    if (argc != 3) {  
      NSLog(@"使用说明： %s 
     <温度> 
      <转换方向>
       \n", argv[0]);  
      return EXIT_FAILURE;  
    }  
    double temperature = atof(argv[1]);  
    NSString *direction = argv[2];  
    if (!direction || [direction length] != 2) {  
      NSLog(@"错误：转换方向必须是 'C' 或 'F'\n");  
      return EXIT_FAILURE;  
    }  
    double convertedTemp;  
    if ([direction isEqualToString:@"C"]) {  
      convertedTemp = [converter celsiusToFahrenheit:temperature];  
    } else {  
      convertedTemp = [converter fahrenheitToCelsius:temperature];  
    }  
    NSLog(@"转换结果： %.6f\n", convertedTemp);  
    [pool release];  
    return EXIT_SUCCESS;  
  }  
  @implementation TemperatureConverter  
  - (double)celsiusToFahrenheit:(double)celsiusTemperature) {  
    return (celsiusTemperature * 9/5) + 32;  
  }  
  - (double)fahrenheitToCelsius:(double)fahrenheitTemperature) {  
    return (fahrenheitTemperature - 32) * 5/9;  
  }  
  @end