返回static_cast <int> C ++和C

Question

I would like to know about C and C++ language.

C++ uses:

return static_cast<int>

How can I transform return static_cast<int> to C?

For example:

• C printf()
• C++ cout

Answer 1

C style casting is simply prefixing the value with the type in parentheses. Instead of

static_cast<type>(value)

you simply do

(type)value

eg

static_cast<int>(x)

becomes

(int)x

Or you could do

#ifdef __cplusplus
    #define STATIC_CAST(Type_, Value_) static_cast<Type_>(Value_)
#else
    #define STATIC_CAST(Type_, Value_) (Type_)(Value_)
#endif

and use one invocation for both languages

STATIC_CAST(int, x) // C++ static_cast<int>(x), C (int)(x)

The extra parentheses in the C version around the Value_ aren't required for simple cases but are there because this is a macro and if you said

STATIC_CAST(int, 1.0 + 2.0)

you don't want it to expand to

(int)1.0 + 2.0

but want it to expand to

(int)(1.0 + 2.0)

Note that C++ allows the C form of casting but the templated cast mechanism is preferred by C++ engineers.