C++ parenthesis matching application

I have to write a function that accepts a string and returns a bool. The string passed in is a series or different parenthesis opened or closed ex.({[]}) and returns whether the 'parens' are well-balanced. This has to be implemented by adding items to a stack. I am getting the following error: parenMatching_demo.cpp:18:12: error: no match for 'operator==' in 'c == '(' The psudocode is: ``` matcher(expression) for each character in expression if the character is an opener push on stack else if the character is a closr if stack is empty return false if the (opener at) the top of the stack does not match the closer return false pop the stack if the stack is not empty return false return true ``` This is what I have. ``` template <typename T> bool parenMatching(string c) { stack<string> s; for (int i = 0; i < s.size(); i++) { if (c == '(' || c == '[' || c == '{' || c == '<') s.push(c); else if (c == ')' || c == ']' || c == '}' || c == '>') { if (s.empty()) return false; if (s.top() != '(' || s.top() != '[' || s.top() != '{' || s.top() != '<') return false; s.pop(); } } } ```