i get always null expretion

Question

1.00/5 (1 vote)

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i need help
plz
here is my code:

C#

class structFile
{
	String filename="";
	int words=0;
	int matchs=0;
	int semiMatchs=0;
	int precent=0;
	String source="";
	
	void structFile()
	{
		this.filename="BroadCast";
		this.words=0;
		this.matchs=0;
		this.semiMatchs=0;
		this.precent=0;
		this.source="->";
	}
}

C#

public class testGUI extend JFrame
{
/*
some funtion the show me tables in JFrame
*/
public static void main ( String[] args )
{
		structFile file10[]=new structFile[10];
		for(int k=0;k<file10.length;k++)
		{
			file10[k].structFile();
		}
System.out.println(file10[some index between 1-10]);
}
}

but i get allways null pointer Expretion

Posted 13-Jan-16 7:14am

komokom

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Thomas Daniels · Accepted Answer · 2016-01-13T07:36:00

Solution 1

After the initialization of the array, all values are null, not an instance of the structFile class, so you cannot call the structFile method on them. Before calling this method, create a new class instance:

Java

for(int k = 0; k < file10.length; k++)
{
    file10[k] = new structFile();
    file10[k].structFile();
}

Posted 13-Jan-16 7:36am

Thomas Daniels

Comments

Sergey Alexandrovich Kryukov 13-Jan-16 15:09pm

Right, a 5.
—SA

Thomas Daniels 13-Jan-16 15:12pm

Thank you.