正确示范1
score = int(raw_input(‘input score:\n‘))
if score >= 90:
grade = ‘A‘
if score <90 and score >= 60:
grade = ‘B‘
if score < 60:
grade = ‘C‘
print ‘%d belongs to %s‘ % (score,grade)
正确示范2
score = int(raw_input(‘input score:\n‘))
if score >= 90:
grade = ‘A‘
elif score >= 60:
grade = ‘B‘
else:
grade = ‘C‘
print ‘%d belongs to %s‘ % (score,grade)
错误示范1
score = int(raw_input(‘input score:\n‘))
if score >= 90:
grade = ‘A‘
#下面的if和else作为一个组合了，会导致99 belongs to C。
if score <90 and score >= 60:
grade = ‘B‘
else:
grade = ‘C‘
print ‘%d belongs to %s‘ % (score,grade)
错误示范2
score = int(raw_input(‘input score:\n‘))
if score >= 90:
grade = ‘A‘
#下面的if和else作为一个组合了，会导致99 belongs to B。
if score >= 60:
grade = ‘B‘
else:
grade = ‘C‘
print ‘%d belongs to %s‘ % (score,grade)
if条件判断
原文：https://www.cnblogs.com/myshuzhimei/p/11753863.html
