C++ Programming Activity: Linked List Stack and Brackets Explain the flow of the main code not necessarily every line, as long as you explain what the important parts of the code do. The code is already correct, just explain the flow SEE ATTACHED PHOTO FOR THE PROBLEM INSTRUCTIONS int main(int argc, char** argv) {     SLLStack* stack = new SLLStack();     int test;     int length;     string str;     char top;     bool flag = true;     cin >> test;     switch (test) {         case 0:             getline(cin, str);              length = str.length();              for(int i = 0; i < length; i++){                 if(str[i] == '{' || str[i] == '(' || str[i] == '['){                     stack->push(str[i]);                 } else if (str[i] == '}' || str[i] == ')' || str[i] == ']'){                     if(!stack->isEmpty()){                         top = stack->top();                         if(top == '{' && str[i] == '}' || top == '(' && str[i] == ')' || top == '[' && str[i] == ']'){                              stack->pop();                         } else {                             cout << "not accepted";                              flag = false;                             break;                                          }                     } else {                         cout << "not accepted" << endl;                          flag = false;                         break;                     }                 }             }             if(flag == true){                 if(!stack->isEmpty()) {                     cout << "not accepted";                 } else {                     cout << "accepted";                 }             }             break;