SYNOPSIS:              #include <cassert>
                            void assert(bool expression);
   
     DESCRIPTION:  This macro is useful for putting diagnostics into programs.
         When it is executed, if expression is false (zero), assert() prints:
            execFile: XYZ:NNN: function(): Assertion `expression' failed.
         on the standard error output and aborts.  In the error message, XYZ is
         the source file name and NNN the source line number of the assert().
             Compiling with the C++ (g++ or c++) compiler option -DNDEBUG, or
         with the preprocessor control statement "#define NDEBUG" ahead of the
         "#include <cassert>" statement, stops assertions from being compiled
         into the program.
   
     $ pr -n -t -e4 assertAR.cpp
         1   // Sample program to:
         2   //   1) Identify if there are nines in an array.
         3   //   2) Illustrate use of #define to create constants.
         4   //   3) Illustrate use of assert macro to catch bad subscript.
         5   //   4) Show array initialization.
         6
         7   #include <iostream>
         8   #include <cassert>
         9   using namespace std;
        10
        11   #define ARSIZE 10
        12
        13   int main()
        14   {
        15       int i = 0;
        16       int Ar[ARSIZE] = {0,1,-1,9,5,9,3,0,545,7};
        17
        18       while ( i <= ARSIZE )
        19       {
        20           cerr << "Searching Ar[" << i << "] \n";
        21           assert( i<ARSIZE );
        22           if (Ar[i] == 9)
        23               cerr << "Found another nine! \n";
        24           i++;
        25       }
        26       return 0;
        27   } // end main
     
     $ c++ assertAR.cpp -o assertAR

     $ assertAR
     Searching Ar[0]
     Searching Ar[1]
     Searching Ar[2]
     Searching Ar[3]
     Found another nine!
     Searching Ar[4]
     Searching Ar[5]
     Found another nine!
     Searching Ar[6]
     Searching Ar[7]
     Searching Ar[8]
     Searching Ar[9]
     Searching Ar[10]
     assertAR: assertAR.cpp:21: int main(): Assertion `i<10' failed.
     Aborted