/* Prog to convert from infix to postfix */
#include<stdio.h>
#include<graphics.h>
#include<stdlib.h>
#include<dos.h>
#include<alloc.h>
#include<process.h>
#include<conio.h>
#define size 10
int j=0;
char sym,p,dup[20],postfix[20],array[20];int top=-1,midx,midy;char infix[20];
int temp=0;
void display();

       // FUNCTION TO DELETE THE CONTENTS OF THE STACK ONE AT A TIME
     char pop()
     {

       // TO CHECK THE OVERFLOW CONDITION
       if(top==-1)
       {
          setcolor(RED);
          settextstyle(7,0,2);
          outtextxy(midx-50,midy-150,"STACK UNDER FLOW");
          return;
        }

     //   clrscr();
        display();  // TO DISPLAY THE DELETED ELEMENT
        settextstyle(0,0,0);


return (array[top--]);

     }


// FUNCTION FOR THE INSERTING ELEMENTS TO THE TOP
      void push(char sym)
      {
    if(top==size-1)
    {
      setcolor(BLUE);
      settextstyle(5,0,2);
      outtextxy(midx-50,midy-150,"STACK OVERFLOW");
      return;
     }

    array[++top]=sym; // COPY THE INSERTED ITEM INTO THE
                  // ARRRAY AND INCREMENT THE TOP
       // clrscr();

     display();  // DISPLAY THE COPIED ELEMENT ON THE STACK

       }

       // TO DISPLAY THE CONTENTS OF THE STACK
        void display()
        {
           int n,i,increment=0;

          setfillstyle(SOLID_FILL,BLACK);
          floodfill(2,2,BLACK);
         rectangle(0,0,getmaxx(),getmaxy());

         /* INSTRUCTIONS FOR THE BEGGINERS */
          setcolor(GREEN);
        settextstyle(7,0,2);
        settextstyle(0,0,1);
        setcolor(6);
         // PLACE THE NAME AT THE BOTTOM AND TOP OF THE STACK
         outtextxy(midx+30,midy-100,"Index");
         outtextxy(midx+105,midy+100,"Bottom");

         // PLACE THE INDEX ELEMENTS AT PROPER PLACE

          outtextxy(midx+55,midy+90,"0");
          outtextxy(midx+55,midy+70,"1");
          outtextxy(midx+55,midy+50,"2");
          outtextxy(midx+55,midy+30,"3");
          outtextxy(midx+55,midy+10,"4");
          outtextxy(midx+55,midy-10,"5");
          outtextxy(midx+55,midy-30,"6");
          outtextxy(midx+55,midy-50,"7");
          outtextxy(midx+55,midy-70,"8");
          outtextxy(midx+55,midy-90,"9");

          // TWO LINES FOR CONSTRUCTING THE BASIC STACK
         line(midx+100,midy+100,midx+100,midy-100);
         line(midx+70,midy+100,midx+70,midy-100);

         //JOINING THE BOTTOM OF THE TWO LINE
            line(midx+100,midy+100,midx+70,midy+100);

        // FORMING THE DIFFERRENT LEVEL FOR STORING THE INTEGERS
            line(midx+100,midy+80,midx+70,midy+80);
            line(midx+100,midy+60,midx+70,midy+60);
            line(midx+100,midy+40,midx+70,midy+40);
            line(midx+100,midy+20,midx+70,midy+20);
            line(midx+100,midy,midx+70,midy);

            line(midx+100,midy-20,midx+70,midy-20);
            line(midx+100,midy-40,midx+70,midy-40);
            line(midx+100,midy-60,midx+70,midy-60);
            line(midx+100,midy-80,midx+70,midy-80);


         /*  DISPLAYING THE INSERTED AND DELETED ELEMENTS TO AND
             FROM THE STACK ARRAY */
           for (i=0;i<=top;i++)
           {
               setcolor(13);
               settextstyle(7,0,2);
               settextstyle(0,0,0);

            outtextxy(midx+75,midy+90-increment,"a");

             increment+=20;
            }

           }


int prec(char ch)
{
switch(ch)
{
  case '+':
  case '-': return 2;
  case '*':
  case '/': return 3;
  case '(': return 4;
}
}

int isEmpty()
{
return top==-1?1:0;
}

int isoperator(char ch)
{
switch(ch)
{
case '+':
case '-':
case '*':
case '/': return 1;
default : return 0;
}
}

int main()
       {
     int ch,i;
     int gdriver = DETECT, gmode, errorcode;
     initgraph(&gdriver, &gmode, "c:\\tc\\bgi");
     errorcode = graphresult();
     if (errorcode != grOk)
    {
       printf("Graphics error: %s\n", grapherrormsg(errorcode));
       printf("Press any key to halt:");
       getch();
       exit(1);
    }

      midx = getmaxx() / 2;
      midy = getmaxy() / 2;
      setcolor(RED);
      settextstyle(7,0,2);
   //FRONT PAGE OR STARTING MODE
        outtextxy(midx-300,midy-100,"INFIX TO POSTFIX CONVERSION USING C GRAPHICS");
        setcolor(9);
        settextstyle(5,0,2);
        outtextxy(midx+150,midy+150,"Developed By,");
        outtextxy(midx+160,midy+170,"Poornima ");
        outtextxy(midx+160,midy+190,"Nishita 6th CS");
            getch();
            clrscr();
            setbkcolor(BLACK);

           setfillstyle(SOLID_FILL,BLACK);
           floodfill(2,2,BLACK);
              rectangle(0,0,getmaxx(),getmaxy());
printf("Enter an expression:");
gets(infix);
clrscr();
for(i=0;infix[i]!='\0';i++)
{
sym=infix[i];

if(sym=='(')
{
  push(sym);
  continue;
}

else if(sym==')')
{
while(1)
{
sym=pop();

if(sym=='(')
break;
postfix[j++]=sym;
}
continue;
}

else if(!isoperator(sym))
    {

     postfix[j++]=sym;
     printf("\n%s",postfix);
     delay(1000);
    }

else
{
while(prec(array[top])>prec(sym) && !isEmpty())
{

  postfix[j++]=pop();

  delay(1000);
}
push(sym);

}
}

while(!isEmpty())
{

postfix[j++]=pop();
delay(1000);

clrscr();
display();
printf("\n%s\n",postfix);
delay(1000);
}
postfix[j]='\0';
printf("\nThe infix expression is: %s",infix);
printf("\nThe postfix expression is: %s",postfix);
getch();
}