Tostring Override in C++

toString override in C++

std::ostream & operator<<(std::ostream & Str, Object const & v) { 
  // print something from v to str, e.g: Str << v.getX();
  return Str;
}

If you write this in a header file, remember to mark the function inline: inline std::ostream & operator<<(... (See the C++ Super-FAQ for why.)

How can I override the ToString() method in C#?

As per your question, to change some characters in the ToString implementation, you need to call the existing ToString method by using the base keyword:

public override string ToString()
{
    return base.ToString().Replace("something", "another thing");
}

Note that if you forget the base keyword it will call itself repeatedly until you get a StackOverflowException.

C4827 warning overriding ToString in C++/CX Metro class

The virtual goes at the beginning, the override goes at the end. Also, you can get rid of the ref new String, the compiler can figure out that you want the string constant to be treated as a String^.

public ref class Foo sealed
{
public:
    virtual String^ ToString() override
    {
        return "This is from class Foo";
    }
};

Override .ToString method c#

You are returning a string that just says the phrase _name + _number + _date + _salary.

What you likely wanted to do is build a string using those fields. If you wanted them all mushed together Concat would work, but it would be highly un-readable

public override string ToString()
{
    return String.Concat(_name, _number, _date, _salary);
}

However what would be better is to use Format and include labels with the values

public override string ToString()
{
    return String.Format("Name:{0}, Number:{1}, Date:{2}, Salary:{3}",_name, _number, _date, _salary);
}

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If you are using C# 6 or newer you can use the following cleaner format

public override string ToString()
{
    return $"Name:{_name}, Number:{_number}, Date:{_date}, Salary:{_salary}";
}

Which is the exact same logic as the previous String.Format version.

override ToString() with override and new keyword

It makes a difference when you do this:

object a = new A(); // notice the type of the variable here!
object b = new B();
Console.WriteLine(a.ToString());
Console.WriteLine(b.ToString());

a.ToString() will not call your implementation of ToString and will instead call object.ToString, which returns the fully qualified type name of the object. b.ToString() will call your implementation.

What you did in B is called overriding. What you did in A is called hiding. Hiding loses its effect when the compile time type of a variable is not that type anymore. Your implementation of ToString will only be called when the compile time type is A.

Learn more here.

Why ToString() method can be overridden without inheritance being involved in C#?

Taken from https://msdn.microsoft.com/en-us/library/system.object(v=vs.110).aspx.

Object class is the ultimate base class of all classes in the .NET Framework; it is the root of the type hierarchy.

Languages typically do not require a class to declare inheritance from
Object because the inheritance is implicit.

Because all classes in the .NET Framework are derived from Object, every method defined in the Object class is available in all objects in the system. Derived classes can and do override some of these methods, including:

• Equals - Supports comparisons between objects.
• Finalize - Performs cleanup operations before an object is
  automatically reclaimed.
• GetHashCode - Generates a number corresponding to the value of the
  object to support the use of a hash table.
• ToString - Manufactures a human-readable text string that describes
  an instance of the class.

Math.net how to create generic ToString() override

You've already created each Matrix as a public property in the Network class, so you can simply access them when you need to.

Network network = new Network(mInput, mResevoir, mOutput);

Console.WriteLine(network.Win);
Console.WriteLine(network.Wres);
Console.WriteLine(network.Wout);

Edit: I just realized that the properties also have a public set method. If you don't want the properties to be changed after the Network variable has been created, you can modify the setters to be private, so the values can only be se from within the class.

public class Network
{           
    public Matrix<double> Win { get; private set; }         // network input matrix
    public Matrix<double> Wres { get; private set; }        // network reservoir matrix
    public Matrix<double> Wout { get; private set; }        // network output matrix

    // constructor
    public Network(Matrix<double> Winput, Matrix<double> Wreservoir, Matrix<double> Woutput)
    {
        Win = Winput;
        Wres = Wreservoir;
        Wout = Woutput;
    }

    public override string ToString()
    {
        return Win.ToString();
    }
}

how to override System.Convert.Tostring Method in c#

Just implement IConvertible in your class. This is what is used by Convert internally (see source)

class MyClass : IConvertible
{
    string IConvertible.ToString(IFormatProvider provider)
    {
        return "whatever";
    }
    // + all the other IConvertible methods
}

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