#N88BASIC '関数。aの平方根を求める Function sqrt(a As Double) As Double Dim x0 As Double Dim d As Double If a < 0 Then'入力が負の時は-1を返す。 sqrt = -1 Exit Function End If d = 0.00000001'差の幅 sqrt = a/2'近似値 Do x0 = sqrt sqrt = 0.5*(x0+(a/x0)) Loop While Abs(sqrt-x0)>d'計算結果の幅が小さくなるまで繰り返す End Function Dim x As Double Input x Print sqrt(x)