for (初期値設定式; ループ条件式; ループ更新式){
...(処理)
}
for (int i=0; i < 10; i++) {
value[i] = value[i] + data[i];
}
private void button3_Click(object sender, EventArgs e)
{
for (int a=0; a <= 10; a++) {
textBox1.Text += a.ToString() + " ";
}
}