/****************** EVALLUATION OF POSTFIX EXPRESSION *****************/
# include<stdio.h>
# include<ctype.h>
# include<string.h>
# include<conio.h>
void main()
{
	char ch,* post;
	int v1,v2,v,stk[20],top=0,max,i;
	clrscr();
	printf("\n\n\t\t**** INPUT ****\n\n");
	puts("Enter the postfix expression  : ");
	gets(post);
	max=strlen(post);
	for(i=0;i<max;i++)
	{
	ch=*(post+i);
	if(tolower(ch) >= 'a' && tolower(ch)<='z')
	{
	v=value(ch);
	stk[top++]=v;
	}
	else
	{
	v2=stk[--top];
	v1=stk[--top];
	v=eval(v1,v2,ch);
	stk[top++]=v;
	}
	}
	printf("\n\n\t\t**** OUTPUT ****\n\n");
	printf("\n----------------------------------------------------");
	printf("\n   THE RESULTANT VALUE IS  : %d",stk[--top]);
	printf("\n----------------------------------------------------");
	getch();
	}

	value(char ch)
	{
	int val;
	printf(" ENTER THE VALUE FOR  %c  : ",ch);
	scanf("%d",&val);
	return(val);
	}

	eval(int a,int b,char ch)
	{
	int c;
	if(ch=='*') c=a*b;
	else  if(ch=='/') c=a/b;
	else  if(ch=='+') c=a+b;
	else  if(ch=='-') c=a-b;
	return(c);
	}