<p>我有这个python代码:</p>
<pre><code>def sqrt(x):
ans = 0
if x >= 0:
while ans*ans < x:
ans = ans + 1
if ans*ans != x:
print x, 'is not a perfect square.'
return None
else:
print x, ' is a perfect square.'
return ans
else:
print x, ' is not a positive number.'
return None
y = 16
sqrt(y)
</code></pre>
<p>输出为:</p>
<pre><code>16 is not a perfect square.
</code></pre>
<p>鉴于这一点非常有效:</p>
<pre><code>x = 16
ans = 0
if x >= 0:
while ans*ans < x:
ans = ans + 1
#print 'ans =', ans
if ans*ans != x:
print x, 'is not a perfect square'
else: print ans, 'is a perfect square'
else: print x, 'is not a positive number'
</code></pre>
<p>我做错什么了?</p>