Integer Expression Evaluator using Infix-to-Postfix conversion and evaluation of Postfix expression

#include<iostream>
#include<string.h>
#include<ctype.h>
#include<stdio.h>
#include<stdlib.h>
using namespace std;

class stack
{
    private:
        int top;
        char A[100];//operator stack array
        int B[100];//operand stack array
    public:
        char pop_oprt();
        void undopop_oprt();
        void push_oprt(char);
        int get_top();
        void displayoprt();
        void init();
        void push_opnd(int);
        int pop_opnd();
};
void stack::init()
{
    top=-1;
}
char stack::pop_oprt()
{
    if(top==-1)
    {
        return 0;
    }
    else
    {
        char t = A[top];
        top--;
        return t;
    }
}
void stack::push_oprt(char val)
{
    top++;
    A[top]=val;
}
void stack::undopop_oprt()
{
    top++;
}
int stack::pop_opnd()
{
    int t = B[top];
    top--;
    return t;
}
void stack::push_opnd(int val)
{
    top++;
    B[top]=val;
}
int stack::get_top()
{
    return top;
}
void stack::displayoprt()
{
    for(int i=top;i>=0;i--)
    {
        cout<<A[i]<<" ";
    }
    cout<<endl;
}
int prcd(char a)
{
    if(a=='(')
    {
        return 0;
    }
    else if(a=='+')
    {
        return 1;
    }
    else if(a=='-')
    {
        return 1;
    }
    else if(a=='/')
    {
        return 2;
    }
    else if(a=='*')
    {
        return 2;
    }
}
int evaluator(char post[100][10],int cnt)
{
    stack opnd;
    opnd.init();
    int i=0;
    while(i<cnt)
    {
        if(isdigit(post[i][0]))
        {
            opnd.push_opnd(atoi(post[i]));
            //opnd.displayoprt();
        }
        else
        {
            int val2 = opnd.pop_opnd();
            int val1 = opnd.pop_opnd();
            if(post[i][0]=='*')
            {
                opnd.push_opnd(val1*val2);
            }
            else if(post[i][0]=='+')
            {
                opnd.push_opnd(val1+val2);
            }
            else if(post[i][0]=='-')
            {
                opnd.push_opnd(val1-val2);
            }
            else if(post[i][0]=='/')
            {
                opnd.push_opnd(val1/val2);
            }
        }
        i++;
    }
    return opnd.pop_opnd();
}
int main()
{
    //char A[100] = "4/2*2+2/2*4";
    char A[100] = "(11+2)*(3+4)";
    stack oprt;
    oprt.init();
    char post[100][10];
    int cnt=00;
    for(int i=0;i<strlen(A);)
    {
        //oprt.displayoprt();
        //getchar();
        int curr_num=0;
        if(isdigit(A[i]))
        {
            while(isdigit(A[i]))
            {
                curr_num = curr_num*10 + A[i]-48;
                i++;
            }
            itoa(curr_num,post[cnt],10);
            cnt++;
        }
        else if(A[i]=='(')
        {
            oprt.push_oprt(A[i]);
            i++;
        }
        else if(A[i]==')')
        {
            while(oprt.pop_oprt()!='(' && oprt.get_top()>-1)
            {
                oprt.undopop_oprt();
                post[cnt][0]=oprt.pop_oprt();
                post[cnt][1]=0;
                cnt++;
            }
            i++;
        }
        else
        {
            //oprt.diplayoprt();
            if(oprt.get_top()==-1)
            {
                oprt.push_oprt(A[i]);
                //cout<<oprt.pop_oprt()<<endl;
            }
            else if(prcd(A[i])>prcd(oprt.pop_oprt()))
            {
                oprt.undopop_oprt();
                oprt.push_oprt(A[i]);
            }
            else
            {
                oprt.undopop_oprt();
                post[cnt][0]=oprt.pop_oprt();
                post[cnt][1]=0;
                cnt++;
                oprt.push_oprt(A[i]);
            }
            i++;
        }
    }
    while(oprt.get_top()>=0)
    {
        post[cnt][0]=oprt.pop_oprt();
        post[cnt][1]=0;
        cnt++;
    }
    cout<<"post-fix"<<endl;
    for(int i=0;i<cnt;i++)
    {
        cout<<post[i]<<endl;
    }
    cout<<"Final value"<<endl;
    cout<<evaluator(post,cnt)<<endl;
}
Output: 91