int btn;
int arrow_x,arrow_y;
int abcd, abcd_t;
int dot;
float aa;
float bb;
float cc;
float out;
float pii;
int action_t;

////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//                                        Void Reset
//
////////////////////////////////////////////////////////////////////////////////////////////////////////

void reset()
{
dot = 0;
aa = 0.0;
bb = 0.0;
cc = 0.0;
out = 0.0;
abcd = 0;
abcd_t = 0;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//                                        Void Show
//
////////////////////////////////////////////////////////////////////////////////////////////////////////

void show()
{
  switch(abcd_t)
  {
  case 0:
    out = aa;
  break;
  case 1:
    out = bb;
  break;
  case 2:
    out = cc;
  break;
  default:
  break;
  }
  nxtEraseRect(1,60,99,50);
    if(out < 10000000 && out >= (-10000000))
    {
      nxtDisplayStringAt(5,58,"%6.2f",out);
    }
    else
    {
      nxtDisplayStringAt(5,58,"ERROR");
      wait10Msec(120);
      reset();
    }
	nxtDrawLine(0,46,0,62);
	nxtDrawLine(1,63,99,63);
return;
}

void step2(int Actio)
{
dot = 0;
abcd = 1;
abcd_t = 1;
action_t = Actio;
show();
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//                                        Void Calc
//
////////////////////////////////////////////////////////////////////////////////////////////////////////

void calc(int Act)
{
  if(Act == 11) // =
  {
    if(aa == 0 || bb == 0)
    {
        if(action_t == 13 || action_t == 14)
        {
          if(action_t == 13)
          {
        	  bb = 0;
            cc = bb;
          }
          else
          {
            if(aa == 0)
            {
        	    bb = 0;
              cc = bb;
            }
            else
            {
              cc = 10000001;
        	    bb = 0;
            }
          }
        }
        else
        {
          if(action_t == 18)
          {
            if(aa == 0)
            {
              cc = aa - bb;
              // cc = cc * (-1);
            }
            else
            {
              cc = aa - bb;
            }
          }
          else
          {
            if(aa == 0)
            {
              cc = bb;
            }
              if(bb == 0)
              {
                cc = aa;
              }
            bb = 0;
          }
        }
    }
    else
    {
      switch(action_t)
      {
      case 13: // *
        cc = aa * bb;
      break;
      case 14: // :(/)
        cc = aa / bb;
      break;
      case 17: // +
        cc = aa + bb;
      break;
      case 18: // -
        cc = aa - bb;
      break;
      }
    }
  aa = cc;
  abcd = 0;
  abcd_t = 0;
  show();
 }
 else
 {
  switch(Act)
  {
  case 10: // dot
    dot = 1;
  break;
  case 12: // +/-
    if(abcd == 1)
    {
    	if(bb != 0)
    	{
        bb = bb * (-1);
      }
    }
    if(abcd == 0)
    {
    	if(aa != 0)
    	{
        aa = aa * (-1);
      }
    }
    abcd_t = abcd;
    show();
  break;
  case 13: // *
    step2(Act);
  break;
  case 14: // :(/)
    step2(Act);
  break;
  case 15: // sqrt
    if(abcd == 0)
    {
    	if(aa > 0)
    	{
        aa = sqrt(aa);
      }
    }
    if(abcd == 1)
    {
    	if(bb > 0)
    	{
        bb = sqrt(bb);
      }
    }
    abcd_t = abcd;
    show();
  break;
  case 16: // x*x
    bb = aa * aa;
    aa = bb;
    bb = 0;
    cc = bb;
    abcd_t = 0;
    show();
  break;
  case 17: // +
    step2(Act);
  break;
  case 18: // -
    step2(Act);
  break;
  case 19: // pi
    if(abcd == 0)
    {
      aa = pii;
    }
      if(abcd == 1)
      {
        bb = pii;
      }
    abcd_t = abcd;
    show();
  break;
  case 20: // Clr
    reset();
    show();
  break;
  }
 }
return;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//                                        Void Num
//
////////////////////////////////////////////////////////////////////////////////////////////////////////

void num(float n)
{
  if(dot > 0)
	{
		float u = n;
		for(int dot_t=1; dot_t<=dot; ++dot_t)
		{
      u = u * 0.1;
		}
	  dot += 1;
	  n = u;
	}
	else
	{
		if(abcd == 1)
	  {
	    bb = bb * 10;
	  }
	    if(abcd == 0)
	    {
	      aa = aa * 10;
	    }
	}
		if(abcd == 1)
	  {
		  if(bb < 0)
	    {
	      n = n * (-1);
	    }
	    bb = bb + n;
	    show();
	  }
	    if(abcd == 0)
	    {
	      if(aa < 0)
	      {
	        n = n * (-1);
	      }
	      aa = aa + n;
	      show();
	    }
return;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//                                        Void Draw Button
//
////////////////////////////////////////////////////////////////////////////////////////////////////////

void draw_btn(byte left, byte top, byte width, byte height, string text)
{
nxtDisplayStringAt((left+2),((top+height)-3),"%s", text);
nxtDrawLine(left,(top+1),left,((top+height)-1));
nxtDrawLine((left+1),(top+height),((left+width)-1),(top+height));
return;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//                                        Task Click
//
////////////////////////////////////////////////////////////////////////////////////////////////////////

task click()
{
PlaySound(soundBlip);
return;
}

////////////////////////////////////////////////////////////////////////////////////////////////////////
//
//                                        Task Main
//
////////////////////////////////////////////////////////////////////////////////////////////////////////

task main()
{
dot = 0;
pii = 3.141592654;
byte w1=9;      // Button.Width (Pixel)
byte h=12;      // Button.Height (Pixel)
int x1[7]={0,12,24,36,48,60,72};
int x2[7]={9,21,33,45,57,85,97};
int y1[3]={0,15,30};
int y1c[3]={0,9,24};
int y2c[3]={6,21,36};
	byte a_s=12;
	byte s = 3;
	int g = 45;
	int a_x1[5]={0,1,1,1,2};
	int a_x2[5]={0,5,6,6,4};
  int a_y1[5]={6,4,5,6,6};
  int a_y2[5]={2,0,0,1,6};
	int bl=0,br=93,bu=56,bd=0;
  int xVal,yVal,xU,xL,yU,yL;
  int yUpper,yLower;
  int zUpper,zLower;
  int move=0;
	byte x_t;
	byte y_t;
  typedef struct{
    byte nMsgSize;
    byte nDeviceAddress;
    byte nLocationPtr;
  } TI2C_Output;
  SensorType(S4) = sensorTouch;
  SensorType[S1] = sensorI2CCustomFast;
  wait10Msec(5);
  nI2CBytesReady[S1]=0;
  while(nI2CStatus[S1]== STAT_COMM_PENDING)
    wait1Msec(2);
  byte replyMessage[6];
  TI2C_Output sOutput;
  sOutput.nMsgSize = 2;
  sOutput.nDeviceAddress = 0x02;
  sOutput.nLocationPtr = 0x42;
	arrow_x = 54;
	arrow_y = 48;
	aa = 0.0;
  bb = 0.0;
  cc = 0.0;
	byte x_tmp = arrow_x+1;
	byte y_tmp = arrow_y+1;
	btn = 0;
	abcd = 0;
	abcd_t = 0;
  while(true)
  {
    nI2CBytesReady[S1] = 0;
    sendI2CMsg(S1, sOutput.nMsgSize, 6);
    xU = 0 + g;
    xL = 0 - g;
    yU = 0 + g;
    yL = 0 - g;
      while (nI2CStatus[S1] == STAT_COMM_PENDING)
      wait1Msec(2);
    replyMessage[0] = 0x80;
    replyMessage[1] = 0x80;
    replyMessage[2] = 0x80;
    replyMessage[3] = 0x80;
    replyMessage[4] = 0x80;
    replyMessage[5] = 0x80;
    if (nI2CStatus[S1] == NO_ERR)
    {
      readI2CReply(S1, replyMessage[0], 6);
      yUpper = replyMessage[1];
      zUpper = replyMessage[2];
      yLower = 0xFF & replyMessage[4];
      zLower = 0xFF & replyMessage[5];
      yVal = (yUpper << 2) + yLower;
      xVal = (zUpper << 2) + zLower;
        if(xVal > 511)
          xVal -= 1024;
        if(yVal > 511)
          yVal -= 1024;
    }
    else
    {
    	eraseDisplay();
      nxtDisplayTextLine(3, "i2c err %d", nI2CStatus[S1]);
      wait10Msec(100);
    }
        if(xVal < xU && xVal > xL && yVal < yU && yVal > yL){move = 0;}
        if(xVal < xU && xVal > xL && yVal > yU){move = 1;}
        if(xVal < xL && yVal > yU){move = 2;}
        if(xVal < xL && yVal < yU && yVal > yL){move = 3;}
        if(xVal < xL && yVal < yL){move = 4;}
        if(xVal < xU && xVal > xL && yVal < yL){move = 5;}
        if(xVal > xU && yVal < yL){move = 6;}
        if(xVal > xU && yVal < yU && yVal > yL){move = 7;}
        if(xVal > xU && yVal > yU){move = 8;}
	  x_t = arrow_x;
	  y_t = arrow_y;
		  switch(move)
		  {
		  case 1:
		  		if(y_t < bu){y_t += s;}
		    break;
		  case 2:
		      if(x_t < br)
		      {x_t += s;}
		        if(y_t < bu)
		        {y_t += s;}
		    break;
		  case 3:
		      if(x_t < br){x_t += s;}
		    break;
		  case 4:
		      if(x_t < br)
		      {x_t += s;}
			      if(y_t > bd)
		        {y_t -= s;}
		    break;
		  case 5:
		      if(y_t > bd){y_t -= s;}
		    break;
		  case 6:
		      if(x_t > bl)
		      {x_t -= s;}
		        if(y_t > bd)
		        {y_t -= s;}
		    break;
		  case 7:
		      if(x_t > bl){x_t -= s;}
		    break;
		  case 8:
		      if(x_t > bl)
		      {x_t -= s;}
		        if(y_t < bu)
		        {y_t += s;}
		    break;
		  }
		  	arrow_x=x_t;
		  	arrow_y=y_t;
          if(arrow_x == x_tmp && arrow_y == y_tmp){}else{
	          x_tmp = arrow_x;
	          y_tmp = arrow_y;
		  	    eraseDisplay();
		  	    show();
                draw_btn(x1[0],y1[0],w1,h,"1");
                draw_btn(x1[1],y1[0],w1,h,"2");
                draw_btn(x1[2],y1[0],w1,h,"3");
                draw_btn(x1[3],y1[0],w1,h,"0");
                draw_btn(x1[4],y1[0],w1,h,",");
                draw_btn(x1[5],y1[0],w1,h,"=");
                draw_btn(x1[6],y1[0],21,h,"+/-");
                draw_btn(x1[0],y1[1],w1,h,"4");
                draw_btn(x1[1],y1[1],w1,h,"5");
                draw_btn(x1[2],y1[1],w1,h,"6");
                draw_btn(x1[3],y1[1],w1,h,"*");
                draw_btn(x1[4],y1[1],w1,h,"/");
                draw_btn(x1[5],y1[1],w1,h,"");
                nxtDrawLine(x1[5]+3,y1[1]+4,x1[5]+2,y1[1]+7);
                nxtDrawLine(x1[5]+3,y1[1]+3,x1[5]+5,y1[1]+9);
                nxtDrawLine(x1[5]+6,y1[1]+9,x1[5]+7,y1[1]+9);
                draw_btn(x1[6],y1[1],21,h,"x*x");
                draw_btn(x1[0],y1[2],w1,h,"7");
                draw_btn(x1[1],y1[2],w1,h,"8");
                draw_btn(x1[2],y1[2],w1,h,"9");
                draw_btn(x1[3],y1[2],w1,h,"+");
                draw_btn(x1[4],y1[2],w1,h,"-");
                draw_btn(x1[5],y1[2],w1,h,"");
                nxtDrawLine(x1[5]+2,y1[2]+9,x1[5]+8,y1[2]+9);
                nxtDrawLine(x1[5]+4,y1[2]+3,x1[5]+4,y1[2]+8);
                nxtDrawLine(x1[5]+6,y1[2]+3,x1[5]+6,y1[2]+8);
                nxtSetPixel(x1[5]+7,y1[2]+3);
                nxtSetPixel(x1[5]+2,y1[2]+8);
                draw_btn(x1[6],y1[2],21 ,h,"Clr");
            for(int h=0; h<5; h++) // draw arrow
            {
  	          nxtDrawLine(a_x1[h]+arrow_x,a_y1[h]+arrow_y,a_x2[h]+arrow_x,a_y2[h]+arrow_y);
            }
              nxtDrawLine(96,1,96,41);
              nxtDrawLine(97,42,99,42);
              wait10Msec(a_s);
          }
                    if(SensorValue(S4) == 1)
                    {
                          if(arrow_y >= y1c[0] && arrow_y <= y2c[0])
                          {
                          	wait1Msec(1);
                            for(int k=0;k<7;k++)
                            {
                              if(arrow_x >= x1[k] && arrow_x <= x2[k])
                              {
                                btn = k;
                              }
                            }
                          }
                            if(arrow_y >= y1c[1] && arrow_y <= y2c[1])
                            {
                            	wait1Msec(1);
                              for(int l=0;l<7;l++)
                              {
                            	  wait1Msec(1);
                                if(arrow_x >= x1[l] && arrow_x <= x2[l])
                                {
                                  btn = l+7;
                                }
                              }
                            }
                              if(arrow_y >= y1c[2] && arrow_y <= y2c[2])
                              {
                              	wait1Msec(1);
                                for(int m=0;m<7;m++)
                                {
                                  if(arrow_x >= x1[m] && arrow_x <= x2[m])
                                  {
                                    btn = m+14;
                                  }
                                }
                              }
  switch(btn)
  {
  case 0:
    btn = 1;
  break;
  case 1:
    btn = 2;
  break;
  case 2:
    btn = 3;
  break;
  case 3:
    btn = 0;
  break;
  case 4:
    btn = 10;
  break;
  case 5:
    btn = 11;
  break;
  case 6:
    btn = 12;
  break;
  case 7:
    btn = 4;
  break;
  case 8:
    btn = 5;
  break;
  case 9:
    btn = 6;
  break;
  case 10:
    btn = 13;
  break;
  case 11:
    btn = 14;
  break;
  case 12:
    btn = 15;
  break;
  case 13:
    btn = 16;
  break;
  case 14:
    btn = 7;
  break;
  case 15:
    btn = 8;
  break;
  case 16:
    btn = 9;
  break;
  }
                          if(btn > 9)
                          {
                            calc(btn);
                          }
                          else
                          {
                            num(btn);
                          }
                          StartTask(click);
                          wait10Msec(40);
                      }
  }
return;
}