Home/ Questions/Is there any solution for the no operator "<<" matches these operands visual c++ error?
Next
Answered
Manon Durand
  • 29
Asked: 2022-05-18T11:12:00+00:00 In:

Is there any solution for the no operator “<<" matches these operands visual c++ error?

  • 29

. Advertisement .

..3..

. Advertisement .

..4..

Hi developer experts,
I have a small but frustrating use case, and so far, I couldn’t get my head around this problem & ideal solution. I am running my command and facing one problem with the no operator “<<" matches these operands visual c++.
Below is the command I used:

void Student::getCoursesEnrolled(const vector<Course>& c)
 {
  for (int i = 0; i < c.size(); i++)
  {
  cout << c[i] << endl;
  }
 
 }

When I run it, I get the following error:

Error: No operator matches these operands
  operand types are: std::ostream << const Course

I am looking forward to gaining some knowledge from all experts.
Thank you, guys!

no operator matches these operands visual c++
Share

2 Answers

  1. Best Answer
    Expert

    The cause: The issue is that operator isn’t an overload for the kind of Course objects you’re trying to produce in your statement below. This causes the error “no operator “<<” matches these operands visual c++”.

    cout << c[i] << endl;

    Solution: You must overload this operator or create your own function to output an object of type Course in std::ostream. For example, consider the following is a class Course definition.

    class Course
{
private:
std::string name;
unsigned int duration;
public:
Course() : duration( 0 ) {}
Course( const std::string &s, unsigned int n ) : name( s ), duration( n ) {}
std::ostream & out( std::ostream &os ) const
{
return ( os << "Course name = " << name << ", course duration = " << duration );
}
};

    When you are able to write

    std::vector<Course> v = { { "A", 1 }, { "B", 2 }, { "C", 3 } };

for ( const Course &c : v ) c.out( std::cout ) << std::endl;
    • 11

  2. All I’m trying to do is return the vector.

    You’re not quite right. You are trying to print this using cout. cout doesn’t know how to print Course objects unless you give it an overloaded operator<<. 

    std::ostream& operator<<(std::ostream& out, const Course& course)
{
 out << course.getName(); // for example
 return out;
}

    For more information, see the operator overloading bible on StackOverflow.

    • 22

Leave an answer

You must login to add an answer.

Need An Account,