Functions

Example of function

      #include <stdio.h>

      double CoulombsLaw (double q1, double q2, double r)
      /***********************************************************
      /* Coulomb's law for the force acting on two point charges
      /* q1 and q2 at a distance r.
      /* MKS units are used.
      /**********************************************************/
      {
        double k = 8.9875e9;
        return k * q1 * q2 / (r * r);
      }

      int main ()
      { printf ("%e newtons\n",
                CoulombsLaw (1.6e-19, 1.6e-19, 5.3e-11));
        return 0;
      }

• first token is type of returned value

• second token is function name

• argument names are proceeded by their type

• function body is within { }

• return statement can be expression or variable

• if keyword void is used, no function value is returned

• if no arguments, void can be used, or leave empty