MAIN

  Demonstrate how a C++ main program
  may call a C routine, and live!

  The C++ main program will now call the C routine.

MAIN:
  Set integers I1 and I2, then call the C routine 
  INT_ADD_SUB to compute I3 = I1 + I2.

  I1 = 42
  I2 = 22

INT_ADD_SUB:
  Input I1 = 42.
  Input I2 = 22.
  Output I3 = 64.

  INT_ADD_SUB returned I3 = 64

  Now repeat, but using a C function.

  INT_ADD_FUNC returned I3 = 64

MAIN:
  Set floats R1 and R2, then call the C routine 
  REAL_ADD_SUB to compute R3 = R1 + R2.

REAL_ADD_SUB:
  Input R1 = 42.000000.
  Input R2 = 22.000000.
  Output R3 = 64.000000.

  REAL_ADD_SUB returned R3 = 64

  Now repeat, but using a C function.

  REAL_ADD_FUNC returned R3 = 64

MAIN:
  Set doubles D1 and D2, then call the C routine 
  DOUBLE_ADD_SUB to compute D3 = D1 + D2.

DOUBLE_ADD_SUB:
  Input R1 = 42.000000.
  Input R2 = 22.000000.
  Output R3 = 64.000000.

  DOUBLE_ADD_SUB returned D3 = 64

  Now repeat, but using a C function.

  REAL_ADD_FUNC returned R3 = 64