我可以阻止int typedef隐式转换为int吗？

Question

我想以下不能编译.

typedef int relative_index_t;  // Define an int to only use for indexing.
void function1(relative_index_t i) {
  // Do stuff.
}

relative_index_t y = 1; function1(y);  // I want this to build.
int x = 1; function1(x);               // I want this to NOT build!

有没有办法实现这个目标？

Answer 1

你不能这样做typedef.

请改用以下内容:

enum class relative_index_t : int {};

用法示例:

int a = 0;
relative_index_t b;
b = (relative_index_t)a; // this doesn't compile without a cast
a = (int)b; // this too

如果您更喜欢C++风格的演员表,请关注以下内容:

int a = 0;
relative_index_t b;
b = static_cast<relative_index_t>(a);
a = static_cast<int>(b);

您也可以使用BOOST_STRONG_TYPEDEF.
^{(致@AlexanderPoluektov的积分)}