null pointer exception while reading array
I was trying above example as follows
http://www.go4expert.com/forums/showthread.php?t=1162
Any ideas, suggestions, sample code, links, source code highly appreciated. Thanks in advance
http://www.go4expert.com/forums/showthread.php?t=1162
public class ArrayReading {When try to run getting null pointer exception.
public static void main( String [] args ) {
String[][] Data = null;
//Assign the values, do it either dynamically or statically
//For first fow
Data[0][0] = "S"; //lastname
Data[0][1] = "Pradeep"; //firstname
Data[0][2] = "Kolkata"; //location //Second row
Data[1][0] = "Bhimani"; //lastname
Data[1][1] = "Shabbir"; //firstname
Data[1][2] = "Kolkata"; //location
//Add as many rows you want
//printing
System.out.print("Lastname\tFirstnam e\tLocatio n\n");
for(int i = 0;i<2;i++) {
for(int j = 0;j<3;j++)
{ System.out.print(Data[j]+"\t");
}
//move to new line
System.out.print("\n");
}
}
}
Any ideas, suggestions, sample code, links, source code highly appreciated. Thanks in advance
ASKER
changed. still getting null pointer exception.please advise
SOLUTION
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Be sure you account for both the row position and column position in the array.
//This is missing the [i] increment.
//Also remember toString() will print the String value.
System.out.print(Data[j]+"\t");
//Above should look like this.
System.out.print(Data[i][j].toString()+"\t");
One more time with proper {} indention.
Please take a look at the Java Trails for Arrays Specifically, the "Creating, Initializing, and Accessing an Array" section. Hope that helps.
public class ArrayReading {
public static void main( String [] args ) {
String[][] Data = new String[2][3];
//Assign the values, do it either dynamically or statically
//For first fow
Data[0][0] = "S"; //lastname
Data[0][1] = "Pradeep"; //firstname
Data[0][2] = "Kolkata"; //location
//Second row
Data[1][0] = "Bhimani"; //lastname
Data[1][1] = "Shabbir"; //firstname
Data[1][2] = "Kolkata"; //location
//Add as many rows you want
//printing
System.out.print("Lastname\tFirstname\tLocation\n");
for(int i = 0;i<2;i++) {
for(int j = 0;j<3;j++) {
System.out.print(Data[i][j].toString()+"\t");
} //end j
//move to new line
System.out.print("\n");
}//end i
}//end main
}//end classPlease take a look at the Java Trails for Arrays Specifically, the "Creating, Initializing, and Accessing an Array" section. Hope that helps.
SOLUTION
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ASKER CERTIFIED SOLUTION
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See Java Tutorials: Arrays