c++ - find a value in a vector of class objects -

i have written class-based vector:

class {  private:      string b;      string c;  public:      a(string n, string l) { b = l ;c = n; }      struct finder {           finder(std::string const& n) : name(n) { }             bool operator () ( const & el) const  { return el.b == name; }      private:           std::string name;      };  };   int main()  {      vector<a> a1;      a1.push_back(a("aa","aa"));      a1.push_back(a("bb","bb"));      a1.push_back(a("cc","cc"));      a1.push_back(a("dd","dd"));       vector<string>::iterator it;      = find_if(a1.begin(), a1.end(), a::finder("cc"));      if (it != a1.end()) {          auto pos = - a1.begin();          cout << "cc found @ " << pos ;      } } 

now, want search value in a1. let's want find index of element in "cc" happens.

i found these similar solutions:

search vector of objects object attribute

std::find object member

how can find object in vector based on class properties?

how find object specific field values in std::set?

as implement comments in section, still errors! did miss? guess problem in defining vector::iterator it;

error c2679: binary '=' : no operator found takes right-hand operand of type 'std::_vector_iterator<_myvec>' (or there no acceptable conversion)

and,

error c2678: binary '!=' : no operator found takes left-hand operand of type 'std::_vector_iterator<_myvec>' (or there no acceptable conversion)

you have use standard algorithm std::find_if

it = find_if(a1.begin(), a1.end(), a::finder("cc")); 

take account inner clas should defined like

struct finder {      finder(std::string const& n) : name(n) { }        bool operator () ( const & el) const  { return el.b == name; }  private:      std::string name;  };