简单计算器

def calculator(x):
    for symb in x:
        if symb in ['+', '-', '*', '/']:
            a, b = map(float, x.split(symb))
            if symb == '/' and b == 0:
                print('Wrong!Division by zero!')
            else:
                print('%.4f%s%.4f=%.4f' % (a, symb, b, eval(x)))
            break
    else:
        print('Invalid operation!')

while True:
    try:
        In = input()
        if '+' in In:
            s = In.split('+')
            num1,num2 = map(float,s)
            print("%.4f+%.4f=%.4f"%(num1,num2,num1+num2))
        elif '-' in In:
            s = In.split('-')
            num1,num2 = map(float,s)
            print("%.4f-%.4f=%.4f"%(num1,num2,num1-num2))
        elif '*' in In:
            s = In.split('*')
            num1,num2 = map(float,s)
            print("%.4f*%.4f=%.4f"%(num1,num2,num1*num2))
        elif '/' in In:
            s = In.split('/')
            num1,num2 = map(float,s)
            if num2 == 0:
                print("Wrong!Division by zero!")
            print("%.4f/%.4f=%.4f"%(num1,num2,num1/num2))
        else:
            print("Invalid operation!")
    except:
        break

def cal(x):
    if '+' in x:
        a,b=map(float,x.split("+"))
        return("%.4f+%.4f=%.4f"%(a,b,a+b))
    elif '-' in x:
        a,b=map(float,x.split("-"))
        return("%.4f-%.4f=%.4f"%(a,b,a-b))
    elif '*' in x:
        a,b=map(float,x.split("*"))
        return("%.4f*%.4f=%.4f"%(a,b,a*b))
    elif '/' in x:
        a,b=map(float,x.split("/"))
        if b ==0:
            return("Wrong!Division by zero!")
        else:
            return("%.4f/%.4f=%.4f"%(a,b,a/b))
    else:
        return ("Invalid operation!")

while True:
    try:
        print(cal(input()))
    except:
        break