Bappy assignment3(prob 2)

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
using namespace std;
#define MAXSIZE 5
int number[MAXSIZE];
int top=-1;

void Push(int x){

    if(top == MAXSIZE -1){
        cout<<"Error: Overflow !"<<endl;
        return;
    }

    number[++top] = x;

}

void Pop(){

    if(top == -1)
    cout<<"Error:Underflow."<<endl;

    else
        top--;

}

int Top(){

    //printf("%d\n", number[top]);

    return number[top];
}


void Print(){

    for(int i=0; i<=top; i++){

        cout<<number[i]<<" ";
        }
    cout<<endl;

    }


int main(int argc, char **argv)
{
    string expression;

    cin>>expression;

    int i, op1,op2, sum=0, x;
    char ch;

    for(i=0; i<expression.size(); i++){

        ch = expression[i];

        if(ch == '+' || ch == '-' || ch == '*' || ch == '/'){



            if(ch == '+'){
                op2 = Top(); Pop();
                op1 = Top(); Pop();
                sum = op2+op1;
                //cout<<sum<<endl;
                Push(sum);
                //Print();


                }
            else if(ch == '-'){
                op2 = Top(); Pop();
                op1 = Top(); Pop();
                sum = op1-op2;
                //cout<<sum<<endl;
                Push(sum);

                }
            else if(ch == '*'){
                op2 = Top(); Pop();
                op1 = Top(); Pop();
                sum = op2*op1;
                //cout<<sum<<endl;
                Push(sum);

                }
                else if(ch == '/'){
                op2 = Top(); Pop();
                op1 = Top(); Pop();
                sum = op1/op2;
                //cout<<sum<<endl;
                Push(sum);

                }



        }

    else{

        x = (int) ch -'0';
            //cout<<"push:"<<x<<endl;
            Push(x);
        }

}

cout<<sum<<endl;






    return 0;
}