Dear experts,

Please kindly advise me in how i should write the column operation:

The following is the full codes:

```
import java.util.*;
public class Matrix {
public static void main(String[] args) {
// declare the necessary variables
int N, M;
String operator;
int index;
int sum;
int [][]matrix = new int[101][101];
// we use 0-based arrary types
Scanner sc = new Scanner(System.in);
N = sc.nextInt();
M = sc.nextInt();
for (int i = 0; i < N; i++)
{
for (int j = 0; j < M; j ++)
{
matrix[i][j] = sc.nextInt();
}
}
operator = sc.next();
index = sc.nextInt();
sum = 0;
index--;
// since we 0-based but the problem requires 1-based
if(operator.equals("ROW"))
{
for (int i = 0; i < M; i++)
{
sum += matrix[index][i];
}
}
else
{
// column operation
}
System.out.println(sum);
}
}
```

At the

`// column operation`

, i have tried to code the following:

```
else// if (operator.equals("COLUMN"))
{
// for (int i = 0; i < N; i--)
for (int j = 0; j < M; j++){
sum += matrix[j][index];
} //System.out.println(sum);
}
```

However, it is unable to give me the output of 5 when my input is as the following:

10 6

0 1 0 0 0 1

0 1 0 1 0 1

0 1 1 1 1 0

1 1 1 0 1 0

1 0 1 0 0 0

0 1 0 0 1 1

0 1 1 0 1 1

0 0 0 0 0 0

1 0 0 0 1 0

0 1 1 1 0 0

COLUMN 3

instead i got the output of 3.

Could anyone please kindly guide me.

Thank you so much.