How does “const” differ in C and C++?

Question

How does the const qualification on variables differ in C and C++?

from: Does "const" just mean read-only or something more?

\"What prompted this q

Answer 1

const in C cannot be used to build constant expressions.

For example :

#include 
int main()
{
   int i = 2;
   const int C = 2;
   switch(i)
   {
      case C  : printf("Hello") ;
      break;

      default : printf("World");
   }
}

doesn't work in C because case label does not reduce to an integer constant.