Practical No: -10
Experiment No. 10: In any language program mostly syntax error occurs due to unbalancing
delimiter such as (), {}, []. Write a C++ program using stack to check whether given expression is
well parenthesized or not.
Code:
#include<iostream>
using namespace std;
const int MAX=20;
class Stack
{
char expr[MAX];
int top;
public:
Stack()
{
top=-1;
}
void push(char ch);
char pop();
bool isEmpty();
bool isFull();
void display();
void checkParenthesis();
};
bool Stack::isEmpty()
{
if(top==-1)
return 1;
else
return 0;
}
bool Stack::isFull()
{
if(top==MAX-1)
return 1;
else
return 0;
}
void Stack::display()
{
if(isEmpty()==1)
cout<<"\n Stack is empty";
else
{
for(int i=0;i<=top;i++)
{
cout<<""<<expr[i];
}
}
}
void Stack::push(char ch)
{
if(!isFull())
{
top++;
expr[top]=ch;
}
}
char Stack::pop()
{
if(!isEmpty())
{
char ch=expr[top];
top--;
return ch;
}
else
{
return '\0';
}
}
void Stack::checkParenthesis()
{
cout<<"\n Enter # as a deliminator after expression(At the end) \n";
cout<<"\n Enter Expression:";
cin.getline(expr,MAX,'#');
char ch;
bool flag=0;
for(int i=0;expr[i]!='\0';i++)
{
if(expr[i]=='('||expr[i]=='['||expr[i]=='{')
push(expr[i]);
if(expr[i]==')'||expr[i]==']'||expr[i]=='}')
{
ch=pop();
if((expr[i]==')'&& ch!='(')||(expr[i]==']'&& ch!='[')||(expr[i]=='}'&&ch!='{'))
{
cout<<"\n Expression is not parenthesized At"<<i<<"="<<expr[i];
flag=1;
break;
}
}
}
if(isEmpty()==1 && flag==0)
cout<<"\n Given expression is Well Parenthesized.";
else
cout<<"\n Given expression is not Well Parenthesized.";
}
int main()
{
char ch;
do
{
Stack s;
s.checkParenthesis();
cout<<"\n Do you want to continue?(y/n):";
cin>>ch;
}
while(ch=='y' || ch=='Y');
return 0;
}
