Java Computer Science

I copied the code from the pdf to my editor and tried running it and I got a few errors

Code:

C:\Computer Science 1020\Test Examples>javac Eg.java
Eg.java:3: non-static variable this cannot be referenced from a static context
{ Student s1 = new Student("John",202123456);
               ^
Eg.java:5: non-static variable this cannot be referenced from a static context
Undergrad s2 = new Undergrad("Mary",201234567,"compsci",1);
               ^
Eg.java:44: cannot find symbol
symbol  : constructor Student()
location: class Eg.Student
{
^
3 errors

Code:

public class Eg
{ public static void main(String[] args)
{ Student s1 = new Student("John",202123456);
System.out.println(s1.toString());//calls Student’s
Undergrad s2 = new Undergrad("Mary",201234567,"compsci",1);
System.out.println(s2.toString());//calls Undergrad’s
}


public class Student
{
private String name;
private long number;

public Student(String aName, long aNumber)
{ this.setName(aName);
this.setNumber(aNumber);
}

public void setName(String aName)
{ this.name = aName;
}
public String getName()
{ return this.name;
}
public void setNumber(long aNumber)
{ this.number = aNumber;
}
public long getNumber()
{ return this.number;
}
public String toString()
{ return "Student[name=" + this.getName() +
",number=" + this.getNumber() + "]";
}
}



public class Undergrad extends Student
{ 
private String major;
private int year;

public Undergrad(String aName, long aNumber,String aMajor, int aYear)
{ 
}

public void setMajor(String aMajor)
{ this.major = aMajor;
}
public String getMajor()
{ return this.major;
}
public void setYear(int aYear)
{ this.year = aYear;
}
public int getYear()
{ return this.year;
}
public String toString()
{ return "Undergrad[name=" + this.getName() +",number=" + this.getNumber() +",major=" + this.getMajor() +",year=" + this.getYear() + "]";
}
}
}

I'm not really good at computer science but I'm still trying my best.
Can someone correct the mistakes?
Thank you.

 

pdf? did you dl or is it yours? lol

 

uhm.... im not sure if you can put all three classes in one file. i used to separate them.

Code:

public class Eg
{ 
	public static void main(String[] args)
	{ 
		Student s1 = new Student("John",202123456);
		System.out.println(s1.toString());//calls Student’s
		Undergrad s2 = new Undergrad("Mary",201234567,"compsci",1);
		System.out.println(s2.toString());//calls Undergrad’s
	}
}

Code:

public class Student
{
	private String name;
	private long number;

	//Constructor
	public Student(String aName, long aNumber)
	{ 
		this.setName(aName);
		this.setNumber(aNumber);
	}

	//Set-Methode
	public void setName(String aName)
	{ 
		this.name = aName;
	}
	
	public void setNumber(long aNumber)
	{ 
		this.number = aNumber;
	}
	//Get-Methode
	public String getName()
	{ 
		return this.name;
	}

	public long getNumber()
	{ 
		return this.number;
	}
	public String toString()
	{ 
		return "Student[name=" + this.getName() +
	",number=" + this.getNumber() + "]";
	}
}

Code:

public class Undergrad extends Student
{ 
	private String major;
	private int year;

	public Undergrad(String aName, long aNumber,String aMajor, int aYear)
	{ 
[COLOR="#ff0000"]		super(aName, aNumber);
		this.major = aMajor;
		this.year = aYear;[/COLOR]
	}

	public void setMajor(String aMajor)
	{ 
		this.major = aMajor;
	}
	public String getMajor()
	{ 
		return this.major;
	}
	public void setYear(int aYear)
	{ 
		this.year = aYear;
	}
	public int getYear()
	{ 
		return this.year;
	}
	public String toString()
	{ 
		return "Undergrad[name=" + this.getName() +",number=" + this.getNumber() +",major=" + this.getMajor() +",year=" + this.getYear() + "]";
	}
}

 

That doesn't really matter. :nono:

 

Danke -Tisken-.

Now I have to understand this. lol -worship

 

what you dont understand?

 

I think I get it now.
I'm just looking at some notes that I'll be studying this school term.-cool