用结构体的所有实例调用函数

Call function with all instances of a struct

本文关键字：实例 调用 函数 结构体      更新时间：2023-10-16

我想用所有的struct对象调用一个函数。

我需要一个函数，它可以通过只调用STRUCT_A来循环遍历结构对象A_1, A_2。空函数reset_all_structs(??)

示例代码:

#include <iostream>

struct STRUCT_A {
    unsigned char number = 0;
    bool bool_1 = 0;
    bool bool_2 = 0;
} A_1, A_2; // Objects: maybe later A_3, ... , A_x
void print_to_terminal(STRUCT_A &STRUCT_NAME);
void set_bool_1(STRUCT_A &STRUCT_NAME);
void set_bool_2(STRUCT_A &STRUCT_NAME);
void reset_one_struct(STRUCT_A &STRUCT_NAME);
void reset_all_structs();
int main()
{
    set_bool_1(A_1);
    A_1.number = 111;
    set_bool_2(A_2);
    A_2.number = 222;
    std::cout << "A_1:n";
    print_to_terminal(A_1);
    std::cout << "n";
    std::cout << "A_2:n";
    print_to_terminal(A_2);
    std::cout << "n";
    reset_one_struct(A_1); // <-- Reset one struct works, my question ist how to reset all structs with the type STRUCT_A?
    std::cout << "A_1:n";
    print_to_terminal(A_1);
    std::cout << "n";
    set_bool_2(A_1);
    A_1.number = 234;
    std::cout << "A_1:n";
    print_to_terminal(A_1);
    std::cout << "n";
    // Here the question. ???
    // reset_all_structs( STRUCT_A );
    // I want to reset both A_1 and A_2 by calling the function reset_all_structs with all object of the struct "STRUCT_A" and loop through these. Is this possible
    // I don't want to call a function like reset_all_struct(A_1, A_2) because later I will add more objects of struct STRUCT_A.
    std::cout << "Reset A_1 and A_2n";
    std::cout << "A_1:n";
    print_to_terminal(A_1);
    std::cout << "n";
    std::cout << "A_2:n";
    print_to_terminal(A_2);
    std::cout << "n";

    return 0;
}
void print_to_terminal(STRUCT_A &STRUCT_NAME){
    std::cout << "Number: " << (int)STRUCT_NAME.number << "n";
    std::cout << "bool_1: " << (int)STRUCT_NAME.bool_1 << "n";
    std::cout << "bool_2: " << (int)STRUCT_NAME.bool_2 << "n";
    return;
};
void set_bool_1(STRUCT_A &STRUCT_NAME){
    STRUCT_NAME.bool_1 = 1;
    STRUCT_NAME.bool_2 = 0;
    return;
};
void set_bool_2(STRUCT_A &STRUCT_NAME){
    STRUCT_NAME.bool_1 = 0;
    STRUCT_NAME.bool_2 = 1;
    return;
};
void reset_one_struct(STRUCT_A &STRUCT_NAME){
    STRUCT_NAME.number = 0;
    STRUCT_NAME.bool_1 = 0;
    STRUCT_NAME.bool_2 = 0;
    return;
};

void reset_all_structs( ??? ){
// loop through all structs
    return;
};

语言本身不可能遍历相同类型的相同变量。

您可以为结构体创建某种注册表，然后遍历该注册表。比如:

struct STRUCT_A;
std::vector<STRUCT_A*> struct_A_registry;
struct STRUCT_A {
   ...
   // constructor
   STRUCT_A() { struct_A_registry.push_back(this); }
   // destructor
   ~STRUCT_A() { 
      for (std::vector<STRUCT_A*>::iterator it = struct_A_registry.begin(); 
           it != struct_A_registry.end(); ++it) 
        if (*it == this) {
          struct_A_registry.erase(this);
          break;
        }
    }
};

那么你的reset_all_structs将只是

void reset_all_structs() {
  for (std::vector<STRUCT_A*>::iterator it = struct_A_registry.begin(); 
       it != struct_A_registry.end(); ++it) 
    reset_one_struct(**it);
}

或者，如果您在程序的同一行声明所有的STRUCT_A变量，您可以将它们组织成一个数组，这会更简单。

你可以把它们放在一个局部数组中，然后遍历它，像这样:

void reset_all_structs()
{
    // This array can be created locally, and must capture by pointer 
    // arrays of references are illegal in C++.
    STRUCT_A * structs[] = { &A_1, &A_2 };
    for(int i = 0; i < sizeof(structs); i++)
    {
      reset_one_struct(*structs[i]);
    }
}

顺便说一句，你标记了你的问题c++，但这看起来像C。如果你是c++的新手，我建议你把所有的函数都放在STRUCT_NAME的methods里面。至少，将正式的STRUCT_NAME参数重命名为看起来不会与结构本身名称或宏定义冲突的名称。最后，我建议将结构体实例收集到STL容器(如std::vector)中，以简化循环中的迭代和访问。

使用array或更好的structs的vector代替。

struct STRUCT_A {
    unsigned char number = 0;
    bool bool_1 = 0;
    bool bool_2 = 0;
};
typedef struct STRUCT_A Data;

void set_bool_1(Data& data_i) {
    data_i.bool_1 = 1;
}
void set_bool_2(Data& data_i) {
    data_i.bool_1 = 1;
}
void reset_one_struct(Data& data_i) {
    data_i.bool_1 = 0;
    data_i.bool_2 = 0;
    data_i.number = 0;
}
void reset_all_structs(std::vector<Data>& all_data) {
    for(int i = 0; i < all_data.size(); ++i)
        reset_one_struct(all_data[i]);
}
int main()
{
    std::vector<Data> my_data(2);
    set_bool_1(my_data[1]);
    my_data[1].number = 111;
    reset_one_struct(my_data[1]);
    reset_all_structs(my_data);
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