private void equal_Click(object sender, EventArgs e) { bigint b = new bigint(); b.f(calctxt.Text); if (oper == 1) { last += b; calctxt.Text = last.ToString(); latest = b; loper = oper; } if (oper == 2) { last -= b; calctxt.Text = last.ToString(); latest = b; loper = oper; } if (oper == 3) { last *= b; calctxt.Text = last.ToString(); latest = b; loper = oper; } if (oper == 4) { if (loper == 1) { last += latest; calctxt.Text = last.ToString(); } if (loper == 2) { last -= latest; calctxt.Text = last.ToString(); } if(loper==3) { last *= latest; calctxt.Text = last.ToString(); } } oper = 4; }