Bracket Matching C++ code

bracket_matching.cpp

#include <iostream>
#include <stack>


using namespace std;

class bracket_matcher: public stack<char>{
	public:
		bracket_matcher(): stack<char>() { matching = 1;}
		void push_bracket(const char &arg){
			if(isOpeningBracket(arg) && isBracket(arg)){
				stack<char>::push(arg);
			}else if(isBracket(arg)){
				matching = (!stack<char>::empty()) && stack<char>::top()==reverseBracket(arg);
				if(matching)
					stack<char>::pop();
			}
		}

		bool isMatching() const { return matching; }

	private:
		bool matching;
		bool isBracket(const char &c);
		bool isOpeningBracket(const char &c);
		char reverseBracket(const char &c);
};


char bracket_matcher::reverseBracket(const char &c){
	switch(c){
			case '}':return '{';
			case ')':return '(';
			case ']':return '[';
			case '{':return '}';
			case '(':return ')';
			case '[':return ']';

			default: return 0;
	}
}

bool bracket_matcher::isOpeningBracket(const char &c){
		switch(c){
			case '{':
			case '(':
			case '[':return 1;

			default:return 0;
		}
}


bool bracket_matcher::isBracket(const char &c){
		switch(c){
			case '}':
			case ')':
			case ']':
			case '{':
			case '(':
			case '[':return 1;

			default:return 0;
		}
}

int main(){
    int t,i;
    cin >> t;
    for(int a0 = 0; a0 < t; a0++){
        string s;
	    bracket_matcher b;
        cin >> s;
        for(i=0;i<s.length() && b.isMatching();++i){
        	b.push_bracket(s[i]);
        }
        cout << (b.isMatching() && b.empty()?"YES":"NO") << endl;
    }
    return 0;
}