C++ program using stack to check whether given expression is well parenthesized or not

In any language program mostly syntax error occurs due to unbalancing delimiter such as (),{},[].
So today we are going to see a program which checks whether the given expression is well parenthesized or not.
lets take an example:
{c-[(a+b)*c]} is well parenthesized expression
but
{c-[a+b)*c] is not

how to code
use stack data structure
scan the expression from left to right
if element of expression is opening paranthesis  push it in stack
if element of expression is closing paranthesis  the pop the top most element of stack
if match found repeat the loop
else return false

so lets see the implementation of this problem using c++

#include<iostream>
#include<cstring>
using namespace std;

class stack_
{
char stack[10];  //stack is created using array
int top;
public:
stack_():top(-1){} //initialization of top using constructor

void push(char x)  //push function to insert element in stack
{
if(top==9)
cout<<"overflow";
else
{
top++;
stack[top]=x;
}
}

char pop() //pop function to remove the element from stack
{
if(top!=-1)
{

return(stack[top--]);

}
else
cout<<"underflow";

}

bool is_empty() //is_empty function to check whether the stack is empty or not
{
if(top==-1)
return true;
else
return false;
}

bool is_full() //is_full function to check whether the stack is full or not
{
if(top==9)
return true;
else
return false;
}

bool balence(string ex) // main logic starts from here
{
int j=0;
char c[10];
for(int i=0;i<ex.size();i++)
{
if(ex[i]=='('||ex[i]=='{'||ex[i]=='[')
push(ex[i]);
else if(ex[i]==')'||ex[i]=='}'||ex[i]==']')
{
if(is_empty()||!pair(stack[top],ex[i]))
return false;
else
{

c[j]=pop();
j++;
}
}
}
for(int i=0;i<j;i++)
{
cout<<c[i];
}
for(int i=j-1;i>=0;i--)
{
if(c[i]=='(')
cout<<")";
else if(c[i]=='[')
cout<<"]";
else if(c[i]=='{')
cout<<"}";
}
cout<<endl;
return is_empty()?true:false;
}


bool pair(char ope,char cls)
{
if(ope=='('&& cls==')')
return true;
else if(ope=='['&& cls==']')
return true;
else if(ope=='{'&& cls=='}')
return true;
return false;
}

};

int main()
{
stack_ o;
bool b;
int m;
string s="]";
b=o.balence(s);
if(b==true)
cout<<"expression is well parenthesise\n";
else
cout<<"expression is not well parenthesise\n";
return 0;
}