#include<iostream>
using namespace std;
template<class T>
class Stack
{
    int stacksize,top;
    T *astack;
public:
    Stack(int size)
    {
        stacksize=size;
        astack=new T[stacksize];
        top=-1;
    }
    int isEmpty()
    {
        if(top==-1)
        {
            return 1;
        }
        else
        {
            return 0;
        }
    }
    int isFull()
    {
        if(top==stacksize-1)
        {
            return 1;
        }
        else
        {
            return 0;
        }
    }
    void push(T item)
    {
        if(isFull())
        {
            cout<<"stack is full\n";
        }
        else
        {
            top=top+1;
            astack[top]=item;
        }
    }
    T pop()
    {
        if(isEmpty())
        {
            cout<<"stack is empty\n";
        }
        else
        {
            T val;
            val=astack[top];
            top=top-1;
            return val;
            
        }
    }
    T getstacktopval()
    {
        return astack[top];
    }
};
int operatorpre(char op)
{
    int pre;
    switch(op)
    {
        case '+':
        case '-':
            pre=1;
            break;
        case '*':
        case '/':
            pre=2;
            break;
    }
    return pre;
}
int main()
{
    Stack<char>s(20);
    char infix[20],postfix[20];
    cout<<"enter the infix form\n";
    cin>>infix;
    int **0;
    int j=0;
    while(infix[i]!='\0')
    {
        if(isalpha(infix[i]))
        {
            postfix[j]=infix[i];
            i++,j++;
        }
        else
        {
            if(s.isEmpty())
            {
                s.push(infix[i]);
                i++;
            }
            else
            {
                while(((operatorpre(infix[i]))<=(operatorpre(s.getstacktopval())))&&(!s.isEmpty()))
                {
                    postfix[j]=s.pop();
                    j++;
                }
                
                s.push(infix[i]);
                i++;
            }
        
        }
    }
    while(!s.isEmpty())
    {
        postfix[j]=s.pop();
        j++;
    }
    postfix[j]='\0';
    cout<<"the infix form is\t"<<infix<<"\n";
    cout<<"the postfix form is\t"<<postfix<<"\n";
}