Thread: Looking for a few examples..

Code:

//valid : ([(a+b)+c]) + x
//invalid : ([(a+b+c]) + x

#include <iostream>
#include <stack>
#include <string>

using namespace std;

//function declarations
bool Is_Bracket_Open(char);
bool Is_Bracket_Closed(char);
bool Check_Match(char,char);
bool Is_Valid(string);

int main()
{
    string A ="([(a+b)+c])+x";
    string B ="([(a+b+c)+x";
    
    if(Is_Valid(A)==true)
    {
        cout<<"Valid";
    }
    else
     cout<<"***ERR";
    
    
    cin.get();
    cin.get();
}
/*=============================================
  Given: my_string   a string 
  Task:  To determine if the brackets are valid 
  return: Nada
  ============================================*/ 
bool Is_Valid(string my_string)
{
    stack<char> my_stack;//create a stack of chars
    for(int i=0; i<my_string.length(); i++)//iterate through string
    {
       
        char Symbol;
        Symbol = my_string[i];
        
        if(Is_Bracket_Open(Symbol)==true)
        {
            //push open bracket onto stack
            my_stack.push(Symbol);
        }
        if(Is_Bracket_Closed(Symbol)==true)
        {
            char top;
            if (!my_stack.empty())
            {
              top = my_stack.top(); 
                
              if(Check_Match(top,Symbol)==true)
              {
                 //discard opening bracket
               
                  my_stack.pop(); 
                
              }
              else
              {
                
          
                return false;
                break;
              }
            }  
            else
            { 
                return false;
                break;
            }      
        }
        
    }
    if(!my_stack.empty())
    {
      return false;
    } 
    else 
    {
      return true; 
    }      
    
}       
  

bool Is_Bracket_Open(char ch)
{
    if ((ch == '(')||
        (ch == '[')||
        (ch == '{'))
        return true;
    else
        return false;
} 

bool Is_Bracket_Closed(char ch)
{
    if ((ch == ')')||
        (ch == ']')||
        (ch == '}'))
        return true;
    else
        return false;
} 

bool Check_Match(char A,char B) 
{
    if ((A=='(')&&(B==')') )
    {
        return true;
    } 
     else if ((A=='{')&&(B=='}') )
    {
        return true;
    } 
      else if ((A=='[')&&(B==']') )
    {
        return true;
    } 
}

That's an example using the stack... it may or maynot be helpful