How do I fix error CS1520: method must have a return type?

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I am new to programming and after watching youtube or searching online I can't run a program, because it says error CS1520: Method must have a return type.

C#

    using System.Collections;
using System.Collections.Generic;
using UnityEngine;


public class RandomPatrol : MonoBehaviour
{
    public float minX;
    public float maxX;
    public float minY;
    public float maxY;

    Vector2 targetPosition;

    public float speed;

    void Start()
    {
        targetPosition = GetRandomPosition();
    }

    void Update()  
    {
        if ((Vector2)transform.position != targetPosition)
        {
            transform.position = Vector2.MoveTowards(transform.position, targetPosition, speed * Time.deltaTime);
        }
        else
        {
            targetPosition = GetRandomPosition();
        }
    }
    Vector2 GetRandomPosition()
    {
        float randomX = Random.Range(minX, maxX);
        float randomY = Random.Range(minY, maxY);
        return new Vector2(randomX, randomY);
    }
    
}

What I have tried:

I tried putting void in front, but then it shows even more errors.

Posted 27-Nov-21 9:00am

Gnom Ed

Updated 27-Nov-21 10:26am

v3

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OriginalGriff · Accepted Answer · 2021-11-27T09:28:00

Solution 2

In order to return a value - any value - from a method, you have to include the return type in the method signature: void indicates it returns no value, and a type indicates the class or struct that it will return an instance of: Methods - C# Programming Guide | Microsoft Docs[^]

Without a type prefix, it is a constructor, and they cannot return anything as they always return the instance that was created.

You can't "call" a constructor from a constructor, that way just leads to madness and crashing apps when they run out of stack space ...

What you want is probably more like this:

C#

GetRandomPosition(float x = float.MinValue, float y = float.MinValue)
{
    x = x != float.MinValue? x : random.Range(minX, maxX);
    y = y != float.MinValue? y : random.Range(minY, maxY);
    ...
}

Which used optional parameters to do what you wanted.

Posted 27-Nov-21 9:28am

OriginalGriff

Comments

#realJSOP 27-Nov-21 15:38pm

Actually, you *can* call a constructor from a constructor:

public MyClass(int x, int y)
{
    // do something interesting with x
}

public MyClass(int x) : this(x, 0)
{    
    // do something less interesting with x
}

It comes in handy when you want to make init code similar regardless of how the object was constructed.

Of course, you're probably already aware of that. :)

OriginalGriff 27-Nov-21 15:46pm

Yep, but I don't think the OP is quite ready for it yet ... :laugh:
Optional parameters are a bit easier to explain in a little text box!

Gnom Ed 27-Nov-21 15:51pm

Everything is very confusing and nothing is working :(

#realJSOP 27-Nov-21 15:53pm

Update your question with all of the source code in question.

Gnom Ed 27-Nov-21 15:55pm

When I try using your example it says "Assets\RandomPatrol.cs(31,13): error CS0246: The type or namespace name 'Position' could not be found (are you missing a using directive or an assembly reference?)
"

#realJSOP 27-Nov-21 16:25pm

Did you read my code comment? I just guessed at the return type. We don’t know what your class looks like or what you’re trying to do.

Gnom Ed 27-Nov-21 16:28pm

Everything works now. Thank you for the help <3

#realJSOP 27-Nov-21 16:28pm

Try changing Position to Vector2

#realJSOP · Accepted Answer · 2021-11-27T09:28:00

Your GetRandomPosition() method needs a return type. Since you're returning the value returned from an overloaded version of the method, you have to return the same type, something like this:

C#

// This would be the method you're calling from the method in question
private Position GetRandomPosition(float x, float y)
{
   return new Position(x, y);
}

// This is the method you're asking about - I added the Position type to  
// the method prototype. I'm only making a guess as to the type name.
private Position GetRandomPosition()
{
    float randomX = random.Range(minX, maxX);
    float randomY = random.Range(minY, maxY);
    // note the change here too. you can't "new" a method call like you 
    //were doing.
    return this.GetRandomPosition(randomX, randomY);
}