answer = input('Do you want your BMI? :')

if answer:

    print('                Here we go')

h = input('please enter your height (m) : ')

w = input('please enter your weight (kg) : ')

a = float(h)

b = float(w)

BMI = b/a**2

print('BMI = ',BMI)

if BMI < 18.5:

    print('您现在体重过低')

elif 18.5 <= BMI < 24:

    print('您现在指标正常')

elif BMI >= 24:

    print('您现在有点超重')

elif 24 < BMI < 28:

    print('您正处于肥胖前期')

elif 28 <= BMI < 30:

    print('您正处于一度肥胖期')

elif 30 <= BMI < 40:

    print('您正处于二度肥胖期')

else:

 print('您正处于三度肥胖期')

结果是

C:\work>python BMI.py

Do you want your BMI? :yes

                Here we go

please enter your height (m) : 1.70

please enter your weight (kg) : 65

BMI =  22.49134948096886

您现在指标正常

C:\work>python BMI.py

Do you want your BMI? :yes

                Here we go

please enter your height (m) : 1.7

please enter your weight (kg) : 75

BMI =  25.95155709342561

您现在有点超重

C:\work>python BMI.py

Do you want your BMI? :yes

                Here we go

please enter your height (m) : 1.7

please enter your weight (kg) : 70

BMI =  24.221453287197235

您现在有点超重

C:\work>

请指