can not be applied for string and void

Valerie Meunier

5y819Learn iOS Programming

I ger the error :"can not be applied for string and void". Any way to fix it?

auto.Horn() works, but i want it into Console.WriteLine.

Thanks

using System;
class Vehicle
{
public virtual void Horn()
{
Console.WriteLine("horn in general");
}
}

class Car : Vehicle
{
public override void Horn()
{
Console.WriteLine("horn of car does tuut!");
}
}

class Head
{
static void Main(string[] args)
{
Car auto = new Car();
Console.WriteLine("Horn does " + auto.Horn());
}
}

6 Replies

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Sachin Singh5y ago
Accepted answer
you unknowingly doing a strange mistake, you are doing writeline inside writeline , which is not acceptable.
your Horn() methods don't return something it just writes so you can't call it inside writeline.
do this instead.

Note:- The key point is a string can only be concatenated with a string, but Horn() method returns a void.
also, the void can not be concatenated with any datatype as void means just nothing.
class Head
{
     static void Main(string[] args)
{
    Car auto = new Car();
Console.Write("Horn does:");
auto.Horn();
}
}
+5
Sonil Kumar5y ago
@Valerie Meunier - With this, I get the error: "base class is less accessible than class 'Car'.

You are getting this error because your base class has less accessibility than the child class. A parent always has had the same or greater accessibility than a child.

Because, if your child is public and parent class is internal or less accessible, your child will not be able to call the parent from outside the assembly scope. Because as per the constructor calling sequence class always call its parent constructor first. And if your parent is not available outside the assembly (or the scope) it will not able to call that.

So the compiler is intelligent enough to stop that at compile time.
+1
Valerie Meunier5y ago
Yes, i didn't see it. Stupid.
Thanks
+1
Pranam Bhat5y ago
You need to make everything to "public" class.
+1
Valerie Meunier5y ago
Thanks for replying, but do you mean:
public class Car : Vehicle
{
public override void Horn()
{
Console.WriteLine("horn of car does tuut!");
}
}

With this, i get the error: "base class is less accessible than class 'Car'
+1
Pranam Bhat5y ago
Correct :

public class Car : Vehicle
+2