Introduction

An expression can be explicitly converted or cast to type T using dynamic_cast<T>, static_cast<T>, reinterpret_cast<T>, or const_cast<T>, depending on what type of cast is intended.

C++ also supports function-style cast notation, T(expr), and C-style cast notation, (T)expr.

Syntax

• simple-type-specifier \\( \\)
• simple-type-specifier \\( expression-list \\)
• simple-type-specifier braced-init-list
• typename-specifier \\( \\)
• typename-specifier \\( expression-list \\)
• typename-specifier braced-init-list
• dynamic_cast \\< type-id \\> \\( expression \\)
• static_cast \\< type-id \\> \\( expression \\)
• reinterpret_cast \\< type-id \\> \\( expression \\)
• const_cast \\< type-id \\> \\( expression \\)
• \\( type-id \\) cast-expression

Remarks

All six cast notations have one thing in common:

• Casting to an lvalue reference type, as in dynamic_cast<Derived&>(base), yields an lvalue. Therefore, when you want to do something with the same object but treat it as a different type, you would cast to an lvalue reference type.
• Casting to an rvalue reference type, as in static_cast<string&&>(s), yields an rvalue.
• Casting to a non-reference type, as in (int)x, yields a prvalue, which may be thought of as a copy of the value being cast, but with a different type from the original.