c++ - 遍历 constexpr 数组

Question

我有以下文件:

测试.hpp

class Test {
    static constexpr const char* array[] {
        "hello",
        "world",
        "!"
    };
  public:   
    void do_stuff();
    
};

测试.cpp

void Test::do_stuff() {
  for(int i = 0; i < 3; ++i) {
    std::cout << array[i];
  }
}

int main() {
  Test object;
  object.do_stuff();

}

失败并出现以下链接错误:

undefined reference to `Test::array'

那么我怎样才能定义一个 constexpr 数组然后遍历它呢？

Answer 1

static 成员需要离线声明或显式inline:

来自 C++17:

inline static constexpr const char* array[] {

其他解决方案:

#include <iostream>

class Test {
    static constexpr const char* array[] {
        "hello",
        "world",
        "!"
    };
  public:   
    void do_stuff();
    
};

constexpr char* Test::array[];

void Test::do_stuff() {
  for(int i = 0; i < 3; ++i) {
    std::cout << array[i];
  }
}

int main() {
  Test object;
  object.do_stuff();

}