1. Member
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Nov 2007
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## Adding numbers in a 2 dimensional array

Hey guys I'm new to java and I am looking for some help. I want to create a program that will add up the numbers in a two dimensional array. I have most of the code down but I keep getting errors.

Here's my code:

class averageNum {
// initialize # of rows
int[][] arr = { { 1, 0, 12, -1 },
{ 7, -3, 2, 5 },
{ -5, -2, 2, 9 }
};

int x;
int sum;

public int sum(int num)
{
int total = 0;
}

public int test(int sum){

for (int i = 0; i < 3; i++)

for (int j = 0; j < 4; i++)
sum = sum + arr[i][j];

}

public static void main (String[] args){

System.out.println(sum);
}

I get an error in my main method saying "non static variable sum cannot be referenced from a static context"

Any help would greatly be appreciated!

2. You need to instantiate an instance of your averageNum class. (BTW it is a good idea to being all of your class names with a capitol letter.) Before you do that, your averageNum needs some touching up.

Java Code:
```public class AverageNum{
//initialize # of rows
int[][] arr = { { 1, 0, 12, -1 },
{ 7, -3, 2, 5 },
{ -5, -2, 2, 9 }
};
public AverageNum(){
//always need a constructor.
}

int x;   //not sure why you need this
int sum;  //you may not need this either.  you can just return the sum from the method

//this method doesn't do anything
public int sum(int num){
int total = 0;
}

public int test(){
int sum = 0;
for(int i = 0; i < arr.length; i++){
for(int j = 0; j < arr[i].length; j++){
sum = sum + arr[i][j];
}
}
return sum;
}

public static void main(String[] args){
AverageNum foo = new AverageNum();
System.out.println(foo.test());

}

}```

3. Member
Join Date
Nov 2007
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ok I understand now. Thank you very much appreciate the help!

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