一、设计一个K线类

1）最低价格（可读写（get,set)）
2）最高价格（可读写（get,set)）
3）平均价格（只读(get) ）

1、KLine.h

#import <Foundation/Foundation.h>

@interface KLine : NSObject{
    @public
    float _highPrice;
    float _lowPrice;
    float _avgPrice;
}

-(void)setHighPrice:(float) heighPrice;
-(float) getHighPrice;
-(void)setLowPrice:(float) lowPrice;
-(float) getLowPrice;
-(float) getAvgPrice;


@end

2、KLine.m

#import "KLine.h"

@implementation KLine
-(void)setHighPrice:(float) heighPrice{
    _highPrice = heighPrice;
    _avgPrice =(_lowPrice + _highPrice)/2;
}
-(float) getHighPrice{
    return _highPrice;
}
-(void)setLowPrice:(float) lowPrice{
    _lowPrice = lowPrice;
    _avgPrice =(_lowPrice + _highPrice)/2;

}
-(float) getLowPrice{
    return _lowPrice;
}
-(float) getAvgPrice{
    //return (_lowPrice + _highPrice)/2;
    return _avgPrice;
}
@end

3、main.h:

#import <Foundation/Foundation.h>
#import "KLine.h"
int main(int argc, const char * argv[])
{

    @autoreleasepool {

        KLine *kline = [KLine new];
        [kline setHighPrice:30.0f];
        [kline setLowPrice:20.0f];
        float avg = [kline getAvgPrice];
        NSLog(@"avg = %.2f",avg);

    }
    return 0;
}