DSL D26

Data Structure Lab :

Practical D26:

 

In any language program mostly syntax error occurs due to unbalancing delimiter such as

(),{},[]. Write C++ program using stack to check whether given expression is well

parenthesized or not.

 // Author : SE CSE GURU  
 
 #include<iostream>  
 #include<string>  
   
 using namespace std;  
   
 class Parenthesis{  
        
      public:  
           int Top,max;  
           char Stack[30];  
             
           Parenthesis(){  
             
           Top=-1;   
           max=29;   
        
      }  
           void push(char);  
           char pull();  
           int isFull();  
           int isEmpty();  
        
 };  
   
 void Parenthesis::push(char ch){  
        
      if(isFull()){  
           cout<<"Stack is Overflow "<<endl;  
      }  
      else{  
              
      Top++;   
      Stack[Top]=ch;   
       
      }  
             
 }  
   
 char Parenthesis::pull(){  
      if(isEmpty()){  
           cout<<"Stack is Underflow "<<endl;  
      }  
      else{  
           return(Stack[Top--]);  
      }  
 }  
   
 int Parenthesis::isFull(){  
      if(Top==max){  
           return 1;  
      }  
      else{  
           return 0;  
      }  
 }  
   
 int Parenthesis::isEmpty(){  
      if(Top==-1){  
           return 1;  
      }  
      else{  
           return 0;  
      }  
 }  
   
 int main(){  
      char ch,choice;  
      string str;  
      int length;  
      do  
      {  
      Parenthesis obj;  
       
      cout<<"Enter expression : "<<endl;   
      cin>>str;  
      length=str.size();   
     
      int flag=0;  
         
      for(int i=0;i<length;i++){  
          
      ch=str[i];  
          
      if (ch=='('||ch=='['||ch=='{'){  
               
          obj.push(ch);  
           }  
      else{  
                  
                if(!( (ch==')' && obj.pull()=='(') || (ch==']' && obj.pull()=='[') || (ch=='}' && obj.pull()=='{') ) ){  
                       
                     flag=1;  
                     break;  
                }  
           }  
        
      }  
        
      if(obj.isEmpty() && flag==0){  
           cout<<"The Expression is well parenthesized :) "<<endl;  
      }  
      else{  
           cout<<"The Expression is NOT well parenthesized :( "<<endl;  
      }  
      cout<<"Do you want to continue (y or n)"<<endl;  
      cin>>choice;  
      }while(choice=='y');  
        
      return 0;  
 }