More on Declarations

Data can be external

      extern double pi;

      double pi = 3.1415;

Internal declaration

      #include <math.h>

      static double exp_random (double mu)
      { return -mu * log (random());
      }

      void simulation1 ()
      { /* declarations and code */
        double x1 = exp_random (2.1);
        /* more code */
      }

• static means local in scope

• definition substitutes for declaration within file

• definition must come before use