trapzd.txt

Visual Basic 常用数学算法集书中收录了所有代码

Sub TRAPZD(A, B, S, N)
    If N = 1 Then
        S = 0.5 * (B - A) * (FUNC(A) + FUNC(B))
        IT = 1
    Else
        IT = 2 ^ (N - 2)
        TNM = IT
        DEL = (B - A) / TNM
        X = A + 0.5 * DEL
        Sum = 0#
        For J = 1 To IT
            Sum = Sum + FUNC(X)
            X = X + DEL
        Next J
        S = 0.5 * (S + (B - A) * Sum / TNM)
    End If
End Sub