Python的for和break循环结构中使用else语句的技巧

for i in range(5):
 if i == 1:
  print 'in for'
else:
 print 'in else'

print 'after for-loop'

# in for
# in else
# after for-loop

for i in range(5):
 if i == 1:
  print 'in for'
  break
else:
 print 'in else'

print 'after for-loop'


# in for
# after for-loop

found = False
for i in range(5):
 if i == 1:
  found = True
  print 'in for'
if not found:
 print 'not found'

print 'after for-loop'


# in for
# after for-loop

#include <iostream> 
#include<math.h> 
using namespace std; 
int main() 
{ 
 int i; 
 float n; 
 for(i=99;i>81;i--) 
 { 
  n=sqrt((float)i); 
  if(n==int(n)) 
  { 
   cout<<i; 
   break; 
  } 
 } 
 if(i==81) //边界判断 
  cout<<"didn't find it!"<<endl; 
 return 0; 
} 

from math import sqrt 
for n in range(99,81,-1): 
 root = sqrt(n) 
 if root == int(root): 
  print n 
  break 
else: 
 print"Didn't find it!" 

from math import sqrt 
for n in range(99,81,-1): 
 root = sqrt(n) 
 if root == int(root): 
  print n 
  break 
 else: 
  print"Didn't find it!"