In development, C ++ and C are mixed.

In development, C ++ and C are mixed.

In actual development, C ++ and C are often mixed. The specific method is as follows:

The C1.c file is a C file written in C:

# Include

 
  
// Use C to write int I = 1; void func () {printf ("% d", ++ I );}

 

CPP1.cpp is a c ++ file written in C ++.

# Include

 
  
Using namespace std; // use C ++ to write // extern int I; extern void func (); int main () {func (); system ("PAUSE "); return 0 ;}

 

An error occurs after compilation because one file is a c file and the other is cpp, and the two are connected to the variable through extern.

Use the extern "C" keyword

Therefore, you must use the extern "C" keyword to compile the C file in the C ++ file. The declaration syntax is as follows:

Extern "C"

{

Content implemented in C Language

}

In the CPP1.cpp file:

# Include

 
  
Using namespace std; // use C ++ to write extern "C" {extern int I; extern void func () ;}int main () {func (); system ("PAUSE"); return 0 ;}

 

In this way, you can compile