Following the wiki.unity scripting tutorial...

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Hello, so i'm just starting scripting in Unity (C#) and i'm hitting a road block, not being able to figure out what i am doing wrong. It's probably a very easy solution, but i really can't see it :s

here's the original script given in the tutorial:

 using UnityEngine;
 using System.Collections;
  
 public class Operation : MonoBehaviour
 {
     // This function has no parameters and returns nothing
     void OnGUI()
     {
         float playerStrength = 10.5f;
         int playerLives = 3;
         string playerName = "Player";
         bool isPlayerAlive = true;
  
         // Player got a 1-Up
         playerLives++;
         GUILayout.Label("Lives: " + playerLives.ToString());
  
         // Player got a special bonus and is now Super Player
         playerName = "Super " + playerName;
         GUILayout.Label(playerName);
  
         // Player got hit by a trash can
         playerStrength--;
         GUILayout.Label("Str: " + playerStrength.ToString());
  
         // Is the player still alive?
         isPlayerAlive = playerStrength > 0.0f;
         playerName += isPlayerAlive ? " Alive" : " Dead";
         GUILayout.Label(playerName);
  
         // Player gets hit by 2 meteors
         // Since we're using an int and float in the operation, the compiler
         // will automatically cast the 2 to a float as an operation requires
         // 2 of the same type to work
         
         playerStrength -= 2 * 5000f;
         GUILayout.Label("Str: " + playerStrength.ToString());
         
         isPlayerAlive = playerStrength > 0.0f;
         playerLives = isPlayerAlive ? playerLives : playerLives-1;
         GUILayout.Label("Lives: " + playerLives.ToString());
  
         playerName += isPlayerAlive ? " Alive" : " Dead";
         GUILayout.Label(playerName);
     }
 }

and here's what i'm trying to do, which is making the playerName being a new string, as opposed to carrying its first state resulting in ("Super Player is Alive Dead")

 using UnityEngine;
 using System.Collections;
  
 public class Operation : MonoBehaviour
 {
     // This function has no parameters and returns nothing
     void OnGUI()
     {
         float playerStrength = 10.5f;
         int playerLives = 3;
         string playerName = "Player";
         bool isPlayerAlive = true;
  
         // Player got a 1-Up
         playerLives++;
         GUILayout.Label("Lives: " + playerLives.ToString());
  
         // Player got a special bonus and is now Super Player
         playerName = "Super " + playerName;
         GUILayout.Label(playerName);
  
         // Player got hit by a trash can
         playerStrength--;
         GUILayout.Label("Str: " + playerStrength.ToString());
  
         // Is the player still alive?
         isPlayerAlive = playerStrength > 0.0f;
         playerName += isPlayerAlive ? " Alive" : " Dead";
         GUILayout.Label(playerName);
  
         // Player gets hit by 2 meteors
         // Since we're using an int and float in the operation, the compiler
         // will automatically cast the 2 to a float as an operation requires
         // 2 of the same type to work
         
         playerStrength -= 2 * 5000f;
         GUILayout.Label("Str: " + playerStrength.ToString());
         
         isPlayerAlive = playerStrength > 0.0f;
         playerLives = isPlayerAlive ? playerLives : playerLives-1;
         GUILayout.Label("Lives: " + playerLives.ToString());
  
         playerName = new string ("Player");
         
         playerName += isPlayerAlive ? " Alive" : " Dead";
         GUILayout.Label(playerName);
     }
 }

The errors i am getting are

"The best overloaded method match for string.String(char*)' has some invalid arguments" - "Argument #1 cannot convert object' expression to type char*'

Any help would be very much appreciate ! Thanks a lot !

Answer 1

Answer by ATMEthan · Jan 23, 2013 at 05:51 PM

To overwrite a string you just do playerName = "player";

To reassign a value to string you shouldn't call a string constructor. That is used for creating a string from a char[] or Int32. (http://msdn.microsoft.com/en-us/library/8s83eyw9.aspx)

If you notice in your error message the compiler says: Cannot convert object(meaning "Player") to type char(meaning any legal char character like 'a'). So what you are trying to do in the constructor is convert string to a char which isn't possible. Here's an example of when you would want to use the string constructor.

return new string(reversedString); //this goes hand and hand with the link below

http://stackoverflow.com/questions/3562078/why-am-i-getting-system-char-printed-out-in-this-case

Hope this helped.

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