I writing a code for paranthesis checking but the complier show me these errors [duplicate]

#include<bits/stdc++.h><br>
using namespace std;<br>
class stack
{
    
    public:
    int size;
    int top;
    char * arr;
};

int isempty(stack*ptr)<br>
{   if (ptr->top==-1)<br>
    {<br>
        return 1;<br>
    }<br>
    return 0;<br>
}<br>
int isFull(stack*ptr)<br>
{<br>
    if (ptr->top==ptr->size-1)<br>
    {<br>
        return 1;<br>
    }<br>
    else<br>
    {<br>
        return 0;<br>
    }<br>
    
    
}<br>
void push(stack*ptr,char value)<br>
{<br>
    if(isFull(ptr))<br>
    {<br>
       cout<<"stack overflow";<br>

    }<br>
    else<br>
    {<br>
        ptr->top++;<br>
        ptr->arr[ptr->top]=value;<br>
        
        
    }<br>
}<br>

char pop(stack*ptr)<br>
{<br>
    if(isempty(ptr))<br>
    {<br>
        cout<<"Stack is empty";<br>
        return -1;<br>
    }<br>
    else<br>
    {<br>
        char v=ptr->arr[ptr->top];<br>
        ptr->top--;<br>
        return v;<br>
    }<br>
    
}<br>

int peek(stack*ptr,int i)<br>
{<br>
    if(ptr->top-i+1<0)<br>
    {<br>
        cout<<"invalid input";<br>
    }<br>
    else<br>
    {<br>
        return ptr->arr[ptr->top-i+1];<br>
    }<br>
    
}<br>

int paranthesisamatch(char*exp)<br>
{      stack*ptr;<br>
       ptr->size=100;<br>
       ptr->top=-1;<br>
       ptr->arr=(char *)malloc(ptr->size * sizeof(char));<br>


       for (int i = 0;exp[i]!="\0"; i++)<br>
       {<br>
           if(exp[i]=='(')<br>
           {<br>
               push(ptr,'(');<br>
           }<br>
           else if (exp[i]==')')<br>
           {<br>
               if (isempty(ptr))<br>
               {<br>
                   return  0;<br>
               }<br>
               pop(ptr);<br>
               
           }<br>
           
           
        {<br>
    if (isempty(ptr))<br>
        {<br>
    return 1;<br>
    }<br>
    return 0;<br>
}<br>

int main()<br>
{<br>
    char*exp= "8+(9*4)";<br>
    if (paranthesisamatch(exp)))<br>
    {<br>
        cout<<"The paranthesis is matching";<br>
    }<br>
    cout<<"The paranthesis is not matching";<br>
    
    return 0;<br>
};<br>

'Error'

C:\Users\91977\Desktop\C++>cd "c:\Users\91977\Desktop\C++\" && g++ tempCodeRunnerFile.cpp -o tempCodeRunnerFile && "c:\Users\91977\Desktop\C++\"tempCodeRunnerFile<br>
tempCodeRunnerFile.cpp:12:13: error: reference to 'stack' is ambiguous<br>
 int isempty(stack*ptr)<br>
             ^~~~~<br>
tempCodeRunnerFile.cpp:3:7: note: candidates are: class stack<br>
 class stack<br>
       ^~~~~<br>
In file included from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\stack:61:0,  <br>
                 from c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\mingw32\bits\stdc++.h:89,      <br>
                 from tempCodeRunnerFile.cpp:1:<br>
c:\mingw\lib\gcc\mingw32\6.3.0\include\c++\bits\stl_stack.h:99:11: note:                 template<class <br>_Tp, class _Sequence> class std::stack<br>
     class stack<br>
           ^~~~~<br>
tempCodeRunnerFile.cp:12:19: error: 'ptr' was not declared in this scope<br>
 int isempty(stack*ptr)<br>
                   ^~~<br>