- (double)Objective C中方法的有效返回类型

Question

我正在尝试从另一个对象返回一个double,然后将其存储到一个新的double中,但我在初始化中得到错误不兼容的类型.我在这里错过了什么？

double gradePoints = 0.0;
double other = [aCourse getGradePoints];
gradePoints = gradePoints + other;

这是我的另一个目标

- (double) getGradePoints{
   return 12.0;
 }

Answer 1

很可能您忘记将getGradePoints方法添加到接口声明中:这将导致该方法被隐式声明为 - (id)getGradePoints; 导致你看到的警告.