C++ explicit

• 禁用 「=」 作為 constructor (copy-initialization)，只能 direct-initialization struct()

• 避免 10, "10" 分不清

• a = 10, a(10)

  • explicit 禁用 a = 10

• a = "10", a("10")

• https://shengyu7697.github.io/cpp-explicit/