打印错误变量未定义

Question

以下代码导致cp_exact未定义错误。我无法弄清楚原因。

基本上，错误是在最终行中的一般情况 print（＆＃34;％10.6f，％10.6f，％10.6f＆＃34;％（a，b，c））。为什么不思考工作？ a，b，c，已定义，但它会抛出一个＆＃34; a未定义＆＃34;错误。

def print_result():
    #Exact call and put based on Black Scholes
    exact_call = V_c(0.75, 0.025, 1, 0, 100, 100, 0.03)
    exact_put = V_p(0.75, 0.025, 1, 0, 100, 100, 0.03)
    #Put these into an array
    cp_exact = [exact_call, exact_put]
    #Euler call and put prices
    cp_euler = CP_Euler(100, 0.08, 0.03, 0.75, 1, 100, 100, 1000)
    #Compute error in call and put prices
    cp_error = Error_Euler(100, 0.08, 0.03, 0.75, 1, 100, 100, 1000, 0.025)
    print("Black-Scholes Euler Discretization Comparison\n\
    with the following parameters: Stock = $100, Strike = $100\n\
    mu = 0.08, r = 0.03, delta = 0.025, sigma = 0.75, T = 1\n\
    dt = 0.01, N = 1000")
    print("Exact Call        Euler Call             Error")
    print("%10.6f %10.6f %10.6f" % (cp_exact[0], cp_euler[0], cp_error[0]))