bool isWeNeeded(size_t i){
auto str = to_string(i);
size_t count = 0;
for(const auto &ch : str){
count += static_cast<size_t>(ch) % 2;
}
return (count == 3);
}
void fuck()
{
for(size_t i = 10000; i < 100000; ++i){
if(isWeNeeded(i)){
cout << i << " ";
}
}
}
原文：http://www.cnblogs.com/wuOverflow/p/4649481.html