c++ - 创建实例化类的数组 - 语法

Question

我有这个功能

# include "Rectangle.hh"
# include "Circle.hh"

void inst_obj (int symbols) {

  for (int i=0; i<symbols ; i++) {
    if (i<10) {
      Rectangle symb(1,2,3);
      //Store symb in an array, like symb_array[i] = symb;
    }
    else {
      Circle symb(1,2,3,4);
      //Store symb in an array, like symb_array[i] = symb;
    }

  }// inst_obj

那我还有一个功能:

  void check_symbols(symbols) {

    for (int i=0; i<symbols; i++) {
      // Check symbol objects, like symb_array[i].return_something
    }
  } // check_symbols

如何以简单的方式存储指向不同对象的指针？ (然后您如何访问它们)？

Answer 1

您可以从 inst_obj 返回指向基础对象的指针 vector ，并将其传递给 check_symbols() 函数。像这样:

// assume Shape is base type of Rectangle and Circle

 std::vector<std::unique_ptr<Shape>> inst_obj (int symbols)
 {
    std::vector<std::shared_ptr<Shape>> v;

   for (int i=0; i<symbols ; i++) 
   {
     if (i<10) 
     {
      v.push_back(std::unique_ptr<Shape>(new Rectangle (1,2,3)));
     }
     else 
     {
       v.push_back(std::unique_ptr<Shape>(new Circle (1,2,3,4)));
     }
     return v;
  }

void check_symbols(std::vector<std::unique_ptr<Shape>>& v) 
{
    for(auto it = v.begin(), it != v.end(); ++it)
    {
      // Check symbol objects, like symb_array[i].return_something
    }
} 

用法:

std::vector<std::unique_ptr<Shape>> v = inst_obj(43);
check_symbols(v);