pre mature program termination

[devendra12121]

I wrote the following code for scientific calc for turbo c++ IDE (code for mouse and graphics was different). However our institute insisted on using bloodshed dev c++ IDE. So I converted entire program to bloodshed dev c++ (the coding for mouse and graphics in the code I am posting here is as supported in dev c++). The graphics work fine, the mouse works as expected but only simple calculation work. Whenever I click on "Tan, Sin, Cos, Log, Pow" buttons, the program terminates...
I am using Win 7 32bit, bloodshed Dev C++ 4.9.9.2 with special graphics.h package that is easily available from google search....

  #define _WIN32_WINNT 0x0500
#include<math.h>
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
#include<graphics.h>
#include <cstdlib>
#include <iostream>
#include <process.h>
#include <windows.h>
#include<winuser.h>
#define P M_PI/180

class BUTTON
{
public:
	int x,y;
	char *ch;
	int len;
	int brd;
	int t;
public:
	BUTTON(){};
	BUTTON(int a,int b,int c,int d,int e,char *k)
	{x=a;y=b;t=c;len=d;brd=e;ch=k;};
	void box(int,int);
	void text();
	void draw();
	void initialize();

}button[]={  BUTTON (230,200,3,40,35,"7"),
	     BUTTON (280,200,3,40,35,"8"),
	     BUTTON (330,200,3,40,35,"9"),
	     BUTTON (380,200,3,40,35,"OFF"),
	     BUTTON (430,200,3,40,35,"CE"),

	     BUTTON (230,245,3,40,35,"4"),
	     BUTTON (280,245,3,40,35,"5"),
	     BUTTON (330,245,3,40,35,"6"),
	     BUTTON (380,245,3,40,35,"*"),
	     BUTTON (430,245,3,40,35,"/"),

	     BUTTON (230,290,3,40,35,"1"),
	     BUTTON (280,290,3,40,35,"2"),
	     BUTTON (330,290,3,40,35,"3"),
	     BUTTON (380,290,3,40,35,"+"),
	     BUTTON (430,290,3,40,35,"-"),

	     BUTTON (230,335,3,40,35,"0"),
	     BUTTON (280,335,3,40,35,"."),
	     BUTTON (330,335,3,40,35,"^"),
	     BUTTON (380,335,3,40,35,"DEL"),
	     BUTTON (430,335,3,40,35,"="),

	     BUTTON (230,380,3,40,35,"Tan"),
	     BUTTON (280,380,3,40,35,"Sin"),
	     BUTTON (330,380,3,40,35,"Cos"),
	     BUTTON (380,380,3,40,35,"Log"),
	     BUTTON (430,380,3,40,35,"Pow"),};



class WINDOW:public BUTTON
{
public:
	WINDOW(){};
	WINDOW(int a, int b,int d,int e){x=a;y=b;len=d;brd=e;};
	void draw();
}cabinate(220,100,260,350);

class SELECT:public BUTTON
{
private:
	char *num[11];
	char *operat;
	int oncedon;
	float number;
	int top,dot;
public:
	SELECT(){top=-1;dot=0;oncedon=0;number=0.0;};
	int check();
	float convert();
	void result_out(float);
	void reset();
	void take_num(int);
	float calculate();
	void output();
	void task(int);
}choice;

void BUTTON::text()
{
setcolor(15);
settextstyle(3,HORIZ_DIR,1);
settextjustify(CENTER_TEXT,CENTER_TEXT);
outtextxy(x+20,y+22,ch);
}

float SELECT::convert()
{
float sum=0.0;
int cond=0,t=0;
int c=0;
for(int i=top;i>=0;i--,c++)
{
if((*num[i])!='.' && cond==0)
{
sum=sum+((*num[i])-48)*pow(10,c);
}
else if(cond==0)
{
sum=sum*pow(10,-(c));
cond=1;
i--;
}
if(cond==1 && i>=0)
{
sum=sum+((*num[i])-48)*pow(10,t);
t++;
}
}
return(sum);
}

void SELECT::reset()
{
top=-1;
oncedon=0;
dot=0;
output();
settextstyle(3,HORIZ_DIR,1);
setcolor(15);
setfillstyle(SOLID_FILL,15);
bar(230,140,470,195);
//line(x,150,x,150);
outtextxy(460,180,"00");
}

void SELECT::output()
{
int dx=460,x;
for(x=231;x<=469;x++)
{
        setcolor(15);
        setfillstyle(SOLID_FILL,15);
        bar(230,140,470,195);
        //line(x,150,x,150);
}
for(int i=top;i>=0;i--)
{
settextstyle(3,HORIZ_DIR,1);
setcolor(15);
setfillstyle(SOLID_FILL,15);
bar(230,140,470,195);
//line(x,150,x,150);
outtextxy(dx,180,num[i]);
dx-=10;
}
}

void SELECT::result_out(float numb)
{
int i=0,dx=470;
char c[5];
char res[30];
//for(x=231;x<=469;x++)
//{
setcolor(15);
setfillstyle(SOLID_FILL,15);
bar(230,140,470,195);
//line(x,150,x,150);
//}
sprintf(res,"%.4f",numb);
settextstyle(3,HORIZ_DIR,1);
setcolor(15);
//setfillstyle(SOLID_FILL,15);
//bar(230,140,470,195);
//line(x,150,x,150);
while(i<=strlen(res))
{
sprintf(c,"%c",res[strlen(res)-i]);
outtextxy(dx,180,c);
i++;
dx-=10;
}
}

float SELECT::calculate()
{
if(*operat=='+')
number=number+convert();
else if(*operat=='-')
number=number-convert();
else if(*operat=='*')
number=number*convert();
else if(*operat=='/')
number=number/convert();
else if(*operat=='^')
number=pow(number,0.5);
else if(*operat=='t')
{
if(convert()/90==1)
{
settextstyle(3,HORIZ_DIR,1);
setcolor(15);
setfillstyle(SOLID_FILL,15);
bar(230,140,470,195);
//line(x,150,x,150);
outtextxy(340,132,"UNDEFINED");
}
else
number=sin(convert()*P)/cos(convert()*P);
}
else if(*operat=='s')
number=sin(convert()*P);
else if(*operat=='c')
number=cos(convert()*P);
else if(*operat=='p')
number=pow(number,convert());
else if(*operat=='l')
number=log10(convert());
else if(*operat=='=')
number=number;

return(number);
}

void SELECT::take_num(int tsk)
{
if(top<=10)
{
if(tsk==16 && dot==0)
{
dot=1;
top++;
num[top]=button[tsk].ch;
}
else if(tsk!=16)
{
top++;
num[top]=button[tsk].ch;
}
}
}

void SELECT::task(int tsk)
{
if(tsk==4)
{
reset();
return;
}

if(tsk==18)
{
top--;
output();
}

if(tsk==3){
closegraph();
exit(1);
}

if(tsk==20 || tsk==21 || tsk==22 || tsk== 23)
{
if(tsk==20)
*operat='t';
if(tsk==21)
*operat='s';
if(tsk==22)
*operat='c';
if(tsk==23)
*operat='l';
oncedon=1;
}

if((tsk<=2 && tsk>=0) || tsk==16 || (tsk<=7 && tsk>=5) || (tsk<=12 && tsk>=10) || tsk==15)
{
take_num(tsk);
output();
}

if(tsk==8 || tsk==9  || tsk==13 || tsk==14 || tsk==17 || tsk==24)
{
if(oncedon==0)
{
number=convert();
if(tsk==24)
*operat='p';
else
operat=button[tsk].ch;
top=-1;
dot=0;
oncedon=1;
return;
}
}

if(tsk==19 || tsk==8 || tsk==9  || tsk==13 || tsk==14 || tsk==17 )
{
if(oncedon==1)
{
number=calculate();

if(tsk==19)
operat=operat;
else
operat=button[tsk].ch;

result_out(number);
top=-1;
dot=0;
}
}
}


int SELECT::check()
{
int x1,y1,b=0,i;
int cond=0;
b=GetKeyState(VK_LBUTTON) & 0x8000;

POINT coord;
GetCursorPos(&coord);
x1=coord.x;
y1=coord.y;
setcolor(15);
//setfillstyle(SOLID_FILL,15);
//bar(230,140,470,195);
//line(x,150,x,150);
//m.getmousepos(x1,y1,b);
if(b!=0)
{
for(i=0;i<25;i++)
{
if(x1<(button[i].x+button[i].len+10) && x1>button[i].x && y1<(button[i].y+button[i].brd+20) && y1>button[i].y)
{
while(b!=0 && x1<(button[i].x+button[i].len+10) && x1>button[i].x && y1<(button[i].y+button[i].brd+20) && y1>button[i].y)
{
b=GetKeyState(VK_LBUTTON) & 0x8000;

POINT coord;
GetCursorPos(&coord);
x1=coord.x;
y1=coord.y;
//m.getmousepos(x1,y1,b);
delay(20);
}
cond=1;
break;
}
}
if(cond==1)
{
button[i].draw();
}
return(i);
}
return(100);
}

void WINDOW::draw()
{
cabinate.box(3,3);
//display.box(15,16);
}

void BUTTON::box(int col,int bcol)
{
setcolor(bcol);
setfillstyle(SOLID_FILL,col);
rectangle(x,y,x+len,y+brd);
floodfill(x+len/2,y+brd/2,bcol);
}

void BUTTON::initialize()
{
for(int i=0;i<25;i++)
{
button[i].draw();
}
}

void BUTTON::draw()
{
box(15,15);
text();
}

int main()
{
          initwindow(700,700,"Scientific Calculator");
          cabinate.draw();
          setfillstyle(SOLID_FILL,15);
	      bar(230,140,470,195);
          button[0].initialize();
          while(1)
          {
                  choice.task(choice.check());
          }
return 0;
}

I am unable to figure out the problem. Please help me....
Thanks....