if (length >= 10)    // Good
if (10 <= length)    // Badwhile (bytes_received < bytes_expected)  // Good
while (bytes_expected < bytes_received)  // Badif (NULL == obj) ...  // Not suggested now
if (obj == NULL) ...  // Good

time_str += (hour >= 12) ? "pm" :"am";  // Badif (hour >= 12) {       // Good: more cleartime_str += "pm";
} else {time_str += "am";
}

return exponent >= 0 ? mantissa * (1 << exponent) : mantissa / (1 << -exponent);  // Badif (exponent >= 0) {     // Goodreturn mantissa * (1 << exponent);
} else {return mantissa / (1 << -exponent);
}

if (results[i] != NULL) {            // Bad
    ....
}
if (results[i] == NULL) continue;    // Good

// Bad : too long, hard to grasp meaning
if line.split(':')[0].strip() == "root":...
// Good : clear enough, understand by the variable name
username = line.split(':')[0].strip()
if username == "root":...

// Bad : five variables in a line
if (request.user.id == document.owner_id) {// user can edit this document...
}
...
if (request.user.id != document.owner_id) {// document is read-only...
}// Good : easy to catch the meaning by variable name
final boolean user_owns_document = (request.user.id == document.owner_id);
if (user_owns_document) {// user can edit this document...
}
...
if (!user_owns_document) {// document is read-only...
}

// Bad
if (!(file_exists && !is_protected)) Error("Sorry, could not read file.");// Good : clear logic
if (!file_exists || is_protected) Error("Sorry, could not read file.");

// Bad : not clear
assert((!(bucket = FindBucket(key))) || !bucket->IsOccupied());// Good : clear enough
bucket = FindBucket(key);
if (bucket != NULL) assert(!bucket->IsOccupied());// except: 可以使用下面这种风格
if (object && object->method()) ...
x = a || b || c;

//集合覆盖
struct Range {int begin;int end;// For example, [0,5) overlaps with [3,8)bool OverlapsWith(Range other);
};// Bad: hard to check , with bug
bool Range::OverlapsWith(Range other) {// Check if 'begin' or 'end' falls inside 'other'.return (begin >= other.begin && begin <= other.end) ||(end >= other.begin && end <= other.end);
}// Good: clear logic , easy to check , bug free
bool Range::OverlapsWith(Range other) {if (other.end <= begin) return false;    // They end before we beginif (other.begin >= end) return false;    // They begin after we endreturn true;     // Only possibility left: they overlap
}

// Bad : too many, hard to check
void AddStats(const Stats& add_from, Stats* add_to) {add_to->set_total_memory(add_from.total_memory() + add_to->total_memory());add_to->set_free_memory(add_from.free_memory() + add_to->free_memory());add_to->set_swap_memory(add_from.swap_memory() + add_to->swap_memory());add_to->set_status_string(add_from.status_string() + add_to->status_string());add_to->set_num_processes(add_from.num_processes() + add_to->num_processes());...
}// Good : easy to check/read
void AddStats(const Stats& add_from, Stats* add_to) {#define ADD_FIELD(field) add_to->set_##field(add_from.field() + add_to->field())ADD_FIELD(total_memory);ADD_FIELD(free_memory);ADD_FIELD(swap_memory);ADD_FIELD(status_string);ADD_FIELD(num_processes);...#undef ADD_FIELD
}

// Bad
now = datetime.datetime.now()
root_message.last_view_time = now// Good
root_message.last_view_time = datetime.datetime.now()

// Bad
var remove_one = function (array, value_to_remove) {var index_to_remove = null;for (var i = 0; i < array.length; i += 1) {if (array[i] === value_to_remove) {index_to_remove = i;break;}}if (index_to_remove !== null) {array.splice(index_to_remove, 1);}
};// Good
var remove_one = function (array, value_to_remove) {for (var i = 0; i < array.length; i += 1) {if (array[i] === value_to_remove) {array.splice(i, 1);  // process immediatelyreturn;}}
};

// Bad : 不必要的变量
boolean done = false;
while (/* condition */ && !done) {...
}
if (...) {done = true;continue;
}// Good : 这类流程控制变量都可以通过if-break/continue来做到
while (/* condition */) {...if (...) {break;}
}

// Bad
PaymentInfo* info = database.ReadPaymentInfo();
if (info) {cout << "User paid: " << info->amount() << endl;
}
// Many more lines of code below ...// Good : 用户看完之后就不需要关心info了
if (PaymentInfo* info = database.ReadPaymentInfo()) {cout << "User paid: " << info->amount() << endl;
}

// Bad
def ViewFilteredReplies(original_id):filtered_replies = []root_message = Messages.objects.get(original_id)all_replies = Messages.objects.select(root_id=original_id)root_message.view_count += 1root_message.last_view_time = datetime.datetime.now()root_message.save()for reply in all_replies:if reply.spam_votes <= MAX_SPAM_VOTES:filtered_replies.append(reply)return filtered_replies// Good : 变量的声明以及使用都聚集在一块了
def ViewFilteredReplies(original_id):root_message = Messages.objects.get(original_id)root_message.view_count += 1root_message.last_view_time = datetime.datetime.now()root_message.save()all_replies = Messages.objects.select(root_id=original_id)filtered_replies = []for reply in all_replies:if reply.spam_votes <= MAX_SPAM_VOTES:filtered_replies.append(reply)return filtered_replies