i have student mark, then one student absent do datagridview

Question

if (dataGridView2.CurrentCell.ColumnIndex < 5)

{

int sum = 0;

//int average = 0;

for (int j = 0; j < dataGridView2.Rows.Count - 1; j++)

{

for (int i = 0; i < dataGridView2.Columns.Count - 2; i++)

{

//char a = 'a';

if (dataGridView2.Rows[j].)

{

}

//{

// a='0';

// dataGridView2.CurrentRow.Cells[i].Value = dataGridView2.CurrentCell.RowIndex.ToString();

//}

//if else(dataGridView2.CurrentCell.RowIndex!='a')

sum += Convert.ToInt32(dataGridView2.Rows[j].Cells[i].Value);

}

} dataGridView2.Rows[dataGridView2.CurrentRow.Index].Cells["dgvctotal"].Value = sum.ToString();

int b = (int.Parse(sum.ToString())) / (int.Parse(dataGridView2.Columns.Count.ToString()) - 2);

dataGridView2.Rows[dataGridView2.CurrentRow.Index].Cells["dgvcaverage"].Value = b.ToString();

}

}