examples/simple_vc_cxx.cpp

   1 /*********************                                                        */
   2 /*! \file simple_vc_cxx.cpp
   3  ** \verbatim
   4  ** Original author: mdeters
   5  ** Major contributors: none
   6  ** Minor contributors (to current version): none
   7  ** This file is part of the CVC4 prototype.
   8  ** Copyright (c) 2009, 2010, 2011  The Analysis of Computer Systems Group (ACSys)
   9  ** Courant Institute of Mathematical Sciences
  10  ** New York University
  11  ** See the file COPYING in the top-level source directory for licensing
  12  ** information.\endverbatim
  13  **
  14  ** \brief A simple demonstration of the C++ interface
  15  **
  16  ** A simple demonstration of the C++ interface.  Compare to the Java
  17  ** interface in SimpleVC.java; they are virtually line-by-line
  18  ** identical.
  19  **/
  20
  21 #include <iostream>
  22
  23 //#include <cvc4.h> // use this after CVC4 is properly installed
  24 #include "smt/smt_engine.h"
  25
  26 using namespace std;
  27 using namespace CVC4;
  28
  29 int main() {
  30   ExprManager em;
  31   SmtEngine smt(&em);
  32
  33   // Prove that for integers x and y:
  34   //   x > 0 AND y > 0  =>  2x + y >= 3
  35
  36   Type integer = em.integerType();
  37
  38   Expr x = em.mkVar("x", integer);
  39   Expr y = em.mkVar("y", integer);
  40   Expr zero = em.mkConst(Rational(0));
  41
  42   Expr x_positive = em.mkExpr(kind::GT, x, zero);
  43   Expr y_positive = em.mkExpr(kind::GT, y, zero);
  44
  45   Expr two = em.mkConst(Rational(2));
  46   Expr twox = em.mkExpr(kind::MULT, two, x);
  47   Expr twox_plus_y = em.mkExpr(kind::PLUS, twox, y);
  48
  49   Expr three = em.mkConst(Rational(3));
  50   Expr twox_plus_y_geq_3 = em.mkExpr(kind::GEQ, twox_plus_y, three);
  51
  52   Expr formula =
  53     em.mkExpr(kind::AND, x_positive, y_positive).
  54     impExpr(twox_plus_y_geq_3);
  55
  56   cout << "Checking validity of formula " << formula << " with CVC4." << endl;
  57   cout << "CVC4 should report VALID." << endl;
  58   cout << "Result from CVC4 is: " << smt.query(formula) << endl;
  59
  60   return 0;
  61 }