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C++ keyword: class

From cppreference.net
C++ language
General topics
Flow control
Conditional execution statements
Iteration statements (loops)
Jump statements
Functions
Function declaration
Lambda function expression
inline specifier
Dynamic exception specifications ( until C++17* )
noexcept specifier (C++11)
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consteval (C++20)
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Boolean - Integer - Floating-point
Character - String - nullptr (C++11)
User-defined (C++11)
Utilities
Attributes (C++11)
Types
typedef declaration
Type alias declaration (C++11)
Casts
Memory allocation
Classes
Class-specific function properties
Special member functions
Templates
Miscellaneous

用法

(since C++11)

示例

class Foo; // 类的前向声明
class Bar  // 类的定义
{
public:
    Bar(int i) : m_i(i) {}
private:
    int m_i;
};
template<class T> // 模板参数
void qux()
{
    T t;
}
enum class Pub // 作用域枚举(C++11起)
{
    b, d, p, q
};
int main()
{
    Bar Bar(1); // 变量Bar隐藏了类型Bar
    Bar Bar2(2); // 编译错误
    class Bar Bar3(3); // 详细类型说明
}

参见

(自 C++11 起)
(自 C++20 起)