Computational Physics Lectures: Introduction to programming (C++ and Fortran)

Contents

Call by value or reference

C++ allows the programmer to use solely call by reference (note that call by reference is implemented as pointers). To see the difference between C and C++, consider the following simple examples. In C we would write

   int n; n =8;
   func(&n); /* &n is a pointer to n */
   ....
   void func(int *i)
   {
     *i = 10; /* n is changed to 10 */
     ....
   }

whereas in C++ we would write

   int n; n =8;
   func(n); // just transfer n itself
   ....
   void func(int& i)
   {
     i = 10; // n is changed to 10
     ....
   }