import math
def sum(a,b):
    return (a+b)
def sub(a,b):
    return (a-b)
def mut(a,b):
    return (a*b)
def div(a,b):
    if(b==0):
        return b
    return (a/b)
def pycomplex(a,b):
    complexoper = input("请输入复数运算")
    if complexoper=="+":
        print("a+b=",a+b)
        return a+b
    if complexoper=="-":
        print("a-b=",a-b)
        return a-b
    if complexoper=="*":
        print("a*b=",a*b)
        return a*b
    if complexoper=="/":
        print("a/b=",a/b)
        return a/b

    
flag = True
while flag:
    a = eval(input("请输入a："))
    b = eval(input("请输入b："))
    operator = input("运算符输入：")
    if operator=="+":
        print("a+b=",sum(a,b))
    if operator=="-":
        print("a-b=",sub(a,b))
    if operator=="*":
        print("a*b=",mut(a,b))
    if operator=="/":
        if b==0:
            print("error")
            continue
        print("a/b=",div(a,b))
    if operator=="com":
        pycomplex(a,b)    
    if operator=="log":
        print("log a b=",math.log(b,a))
    if operator=="sin":
        print("sin(a)=",math.sin(a*3.1415926535/180),",","sin(b)=",math.sin(b*3.1415926535/180))
    if operator=="cos":
         print("cos(a)=",math.cos(a*3.1415926535/180),",","cos(b)=",math.cos(b*3.1415926535/180)) 
    flag = False if input("是否要继续？Y or N\n")=="N" else True