ERROR: no match for 'operator<<" in 'std::cout

Question

I realize this error is usually due to some syntax or type issues but I am not sure how to solve this problem. I think it may do with the type of findRt.

vector&         


        

Answer 1

Why the error?
The compiler reports an error because there is no overloaded version of << operator to handle the type vector which your function findRightTriangles() returns.
<< is overloaded only for most of the built-in data types and not for custom classes.

How to output the vector using cout?
There are two ways:

Solution 1:
A two step procedure:

Step1: You will have to iterate through the vector and cout each contained triangle.

std::vector::const_iterator iter= vec.begin();
for(iter; iter != vec.end(); ++iter)
{
    cout<<*iter; //This is what step 2 provides for
}

Step 2: You will have to overload << for the triangle class as well.

ostream& operator<<( ostream& os, const triangle &) {}

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Solution 2:
One step Solution.
Alternately, You can overload << for vector type itself:

ostream& operator<<( ostream& os, const vector&)
{

}

I would personally prefer the Solution 1. It is more readable & Usually more often than not one would already have an overloaded << for the vector type being used and it could be leveraged.