explicit specifier

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C++语言

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预处理器
注释

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条件执行语句

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循环语句

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跳转语句

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函数声明 Lambda函数声明 inline说明符 异常说明符 (已弃用) noexcept说明符 (C++11)

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说明符

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decltype (C++11)
auto (C++11)
alignas (C++11)

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存储持续期说明符 Initialization

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值类别
求值顺序

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替代表示 字面量 布尔型 - 整型 - 浮点型 字符型 - 字符串 - nullptr (C++11) 用户定义 (C++11)

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属性 (C++11) Types typedef声明 类型别名声明 (C++11) Casts 隐式类型转换 - 显示类型转换 static_cast - dynamic_cast const_cast - reinterpret_cast 内存分配

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类特有的函数属性

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explicit (C++11)
static

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静态成员函数

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指定构造函数和(since C++11)转换运算符,不允许隐式转换
原文:
Specifies constructors and (since C++11) conversion operators that don't allow implicit conversions
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[编辑] 语法

explicit class_name ( params )
explicit operator type ( ) (since C++11)

[编辑] 示例

struct A
{
    A ( int ) {}
 
    operator int() const { return 0; }
};
 
struct B
{
    explicit B(int) {}
    explicit operator int() const { return 0; }
};
 
int main()
{
    // A is has no explicit ctor / conversion, everything is fine
    A a1 = 1;
    A a2 ( 2 );
    A a3 { 3 };
    int na1 = a1;
    int na2 = static_cast<int>( a1 );
 
    B b1 = 1; // Error: implicit conversion from int to B
    B b2 ( 2 ); // OK: explicit constructor call
    B b3 { 3 }; // OK: explicit constructor call
    int nb1 = b2; // Error: implicit conversion from B to int
    int nb2 = static_cast<int>( b2 ); // OK: explicit cast
}


来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/language/explicit&oldid=38208