Given a string containing just characters '(', ')', '(', ')', '[' and ']', determine if the input string is valid. The brackets close in the order, "()" and "() [] {}" are all valid but "(]" and "([)]' are not. Write a COMPLETE code in the main only using stack operations given below. struct nodetype {int info; node type *next;}; class stacktype {public: stack type(); ~stacktype(); void make empty(); void push(int); int pop(); bool isempty(); bool isful (); private: nodetype *top;}