Artimeticki izraz (z4)

#include <iostream>
using namespace std;
main()
{
      string s;
      int a=0, b=0, c=0, d=0;
      bool p = true;

      cin >> s;

      for (int i=0; i<s.length(); i++)
      if (s[i]=='{')
         {
         int j=i;
         while (j<s.length() && s[j]!='}')
             {
                 if(s[j]=='(')
                    a++;
                 if(s[j]==')')
                    b++;
                 if(s[j]=='[')
                    c++;
                 if(s[j]==']')
                    d++;

                 if (s[j]=='}')
                    i=j;

                 j++;
             }
         }

      if (a!=b || c!=d)
         p = false;

      if (p==true)
      {
            a = 0; b = 0; c = 0; d = 0;
            for (int i=0; i<s.length(); i++)
              if (s[i]=='[')
                 {
                 int j=i;
                 while (j<s.length() && s[j]!=']')
                     {
                         if(s[j]=='(')
                            a++;
                         if(s[j]==')')
                            b++;

                         if (s[j]==']')
                            i=j;

                         j++;
                     }
                 }

                 if (a!=b)
                    p = false;

                 if (p==true)
                 {
                             for (int i=0; i<s.length(); i++)
                                 if (s[i]=='(')
                                    c++;
                                 else if (s[i]==')')
                                    d++;

                              if (c!=d)
                              cout << "0" << endl;
                              else cout << "1" << endl;
                 }
                 else cout << "0" << endl;
      }
      else cout << "0" << endl;

      system ("PAUSE");
}