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标题: 同学们帮忙看看代码错误在那 [打印本页]
作者: chain    时间: 2014-6-7 16:17
标题: 同学们帮忙看看代码错误在那
本帖最后由 chain 于 2014-6-7 21:39 编辑

为什么编译器总是报这个错呢？ 求解答 ，谢谢

10.m:83:13: error: unknown receiver 'Point1'; did you mean
      'Point2D'?
    return [Point1 distanceWithOther:point2];
            ^~~~~~
            Point2D
10.m:10:12: note: 'Point2D' declared here
@interface Point2D : NSObject
           ^
10.m:83:20: warning: class method '+distanceWithOther:' not
      found (return type defaults to 'id')
      [-Wobjc-method-access]
    return [Point1 distanceWithOther:point2];
                   ^~~~~~~~~~~~~~~~~
10.m:83:12: error: returning 'id' from a function with
      incompatible result type 'double'
    return [Point1 distanceWithOther:point2];
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1 warning and 2 errors generated.
  1. #import <Foundation/Foundation.h>
  2. #import <math.h>

  4. @interface Point2D : NSObject
  5. {
  6.     double _x;
  7.     double _y;
  8. }

  10. // x的setter和getter
  11. - (void)setX:(double)x;
  12. - (double)x;

  14. // y的setter和getter
  15. - (void)setY:(double)y;
  16. - (double)y;

  18. //同时设置x和y
  19. - (void)setX:(double)x andY:(double)y;

  21. //计算和其他点的距离
  22. - (double)distanceWithOther:(Point2D *)other;

  24. //类方法计算两个点之间的距离
  25. + (double)distanceBetweenPoint1:(Point2D *)point1 andPoint2:(Point2D *)point2;

  27. @end

  29. @implementation Point2D

  31. // x的setter和getter
  32. - (void)setX:(double)x
  33. {
  34.     _x = x;
  35. }
  36. - (double)x
  37. {
  38.     return _x;
  39. }

  41. // y的setter和getter
  42. - (void)setY:(double)y
  43. {
  44.     _y = y;
  45. }
  46. - (double)y
  47. {
  48.     return _y;
  49. }

  51. //同时设置x和y
  52. - (void)setX:(double)x andY:(double)y
  53. {
  54.     _x = x;
  55.     _y = y;
  56. }

  58. //计算和其他点的距离
  59. - (double)distanceWithOther:(Point2D *)other
  60. {
  61.     //计算X的差值
  62.     double xMinus = [self x] - [other x];
  63.     //计算Y的差值
  64.     double yMinus = [self y] - [other y];
  65.     //计算X差值的平方
  66.     double xSquare = pow(xMinus,2);
  67.     //计算Y差值的平方
  68.     double ySquare = pow(yMinus,2);
  69.     //计算xMinus和yMinus的和的开跟
  70.     return sqrt(xSquare + ySquare);
  71. }

  73. //类方法计算两个点之间的距离
  74. + (double)distanceBetweenPoint1:(Point2D *)point1 andPoint2:(Point2D *)point2
  75. {
  76.     //代码重构
  77.     return [Point1 distanceWithOther:point2];
  78. }

  80. @end

  82. int main ()
  83. {
  84.     Point2D *point1 = [Point2D new];
  85.     Point2D *point2 = [Point2D new];
  86.     [point1 setX:20 andY:40];
  87.     [point2 setX:18 andY:28];
  88.     double c = [point1 distanceWithOther:point2];
  89.     double c1 = [Point2D distanceBetweenPoint1:point1 andPoint2:point2];
  90.     NSLog(@"%f----%f",c,c1);
  91.     return 0;
  92. }
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作者: 王海江1    时间: 2014-6-7 21:33
太深奥里，看萌了亲



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