program StableMatching (WifeOf[]);

begin 

  { first we list the women's ranking of the men    }

  f[1][1] = 4; f[1][2] = 2; f[1][3] = 3; f[1][4] = 1;
  f[2][1] = 1; f[2][2] = 3; f[2][3] = 4; f[2][4] = 2;
  f[3][1] = 1; f[3][2] = 2; f[3][3] = 3; f[3][4] = 4;
  f[4][1] = 2; f[4][2] = 1; f[4][3] = 4; f[4][4] = 3;

  { second  we list the men's ranking of the women  } 

  m[1][1] = 2; m[1][2] = 1; m[1][3] = 4; m[1][4] = 3;
  m[2][1] = 2; m[2][2] = 1; m[2][3] = 3; m[2][4] = 4;
  m[3][1] = 2; m[3][2] = 1; m[3][3] = 3; m[3][4] = 4;
  m[4][1] = 3; m[4][2] = 1; m[4][3] = 2; m[4][4] = 4;

  n = 4; 
  m = 0; 
  do n times { record that all men are bachelors } 
     begin m >> m0 = m0 + 1;  b[m] = 1 end; 
  some w; w = 0; 
  do n times { try to marry off the women one by one }
  begin 
    w >> w0 = w0 + 1; 
    find m in [1 .. n] with 
    begin 
      some i; 
      f[w][m] = i;           { m is w's i-th preference }
      b[m] = 1;              { m is still a bachelor    }
      w = WifeOf[m];         { propose woman w to man m } 
      some b[m]; b[m] = 0;   { m is no bachelor anymore }
      donot find rival in [1 .. n] with 
      begin 
        test f[w][rival] < i;{ w prevers rival to m     } 
        either b[rival] = 1  { rival is still unmarried }
        orelse 
          begin 
            b[rival] = 0;       { or .. rival is married   }
            test m[rival][w] < m[rival][WifeOf[rival]];
                         { rival prefers w to his own Wife }
          end 
      end 
    end
  end
end