द्वारा (भयानक) गोल्फों की प्रतिक्रिया में orlp:
सुधार पहले आना चाहिए
- इनमें से अधिकांश कुछ पूर्णांक प्रकारों के लिए टूट जाते हैं। इसमें ओपी से संस्करण शामिल है
- दिलचस्प बात यह है कि वे क्या कर के लिए काम करते
int16_tहैं - तो वहाँ धारणा है। संभवतः 32 बिट्स के लिए बिट शिफ्ट्स +16 की आवश्यकता होगी (जो इन दिनों हर जगह बहुत अधिक है)। यह उन्हें एक चरित्र बड़ा बनाता है ...
इसे लिखने का एकमात्र "सही" तरीका है, IMO (x>3) && (x > y+1), जिसे नीचे x>3&x>y+1(9 वर्णों) तक गढ़ा जा सकता है ।
(आपको वास्तव में (बड़े) अहस्ताक्षरित प्रकारों की संभावना को ध्यान में रखने की आवश्यकता है, खासकर जब से अहस्ताक्षरित-सी + + अभिव्यक्तियों में "संक्रामक" है। मुझे लगता है कि "फिक्सिंग" है कि उपयुक्त static_cast<>एस के साथ उद्देश्य को हराना होगा ...)
अपडेट करें
निम्नलिखित परीक्षणों के साथ मैं यह पता लगाने में सक्षम हुआ कि कौन से भाव वास्तव में मज़बूती से काम करते हैं:
Live On Coliru
#define REPORT(caption, expr) do {\
do_report(caption, [](T x, T y) -> bool { return (expr); }, #expr); } while (false)
template <typename T> struct driver {
static void run() {
std::cout << "\n" << __PRETTY_FUNCTION__ << "\n";
// the only two correct implementations:
REPORT("MASTER" , (x>3) && (x>y+1));
REPORT("GOLF" , x>3&x>y+1);
REPORT("lookup" , "000000000000000000000000111000111100"[x*6+y]-'0');
// failing sometimes:
REPORT("question", (x>3)&(x-y>1));
REPORT("orlp0" , x>3&x-y>1);
REPORT("orlp2" , ~y+x>2>>y);
REPORT("orlp3" , x*x-y*y>9);
REPORT("orlp4" , ~y>x/~3*x);
REPORT("orlp5" , -3>>y>y-x);
REPORT("orlp6" , ~y+x<<y>2);
// failing always
REPORT("orlp1" , -x<~y>4>x);
}
private:
static void do_report(std::string const& caption, bool (*f)(T,T), char const* expression) {
std::string r;
for (T x = 0; x < 6; ++x) for (T y = 0; y < 6; ++y) r += f(x, y)?'1':'0';
bool const correct = "000000000000000000000000111000111100" == r;
std::cout << (correct?"OK\t":"ERR\t") << r << "\t" << caption << "\t" << expression << "\n";
}
};
int main() {
driver<int8_t>::run();
driver<int16_t>::run();
driver<int32_t>::run();
driver<int64_t>::run();
driver<uint8_t>::run();
driver<uint16_t>::run();
driver<uint32_t>::run();
driver<uint64_t>::run();
}
कोलिरु पर आउटपुट, संदर्भ के लिए यहां:
static void driver<T>::run() [with T = signed char]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
OK 000000000000000000000000111000111100 question (x>3)&(x-y>1)
OK 000000000000000000000000111000111100 orlp0 x>3&x-y>1
OK 000000000000000000000000111000111100 orlp2 ~y+x>2>>y
OK 000000000000000000000000111000111100 orlp3 x*x-y*y>9
OK 000000000000000000000000111000111100 orlp4 ~y>x/~3*x
OK 000000000000000000000000111000111100 orlp5 -3>>y>y-x
OK 000000000000000000000000111000111100 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
static void driver<T>::run() [with T = short int]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
OK 000000000000000000000000111000111100 question (x>3)&(x-y>1)
OK 000000000000000000000000111000111100 orlp0 x>3&x-y>1
OK 000000000000000000000000111000111100 orlp2 ~y+x>2>>y
OK 000000000000000000000000111000111100 orlp3 x*x-y*y>9
OK 000000000000000000000000111000111100 orlp4 ~y>x/~3*x
OK 000000000000000000000000111000111100 orlp5 -3>>y>y-x
OK 000000000000000000000000111000111100 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
static void driver<T>::run() [with T = int]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
OK 000000000000000000000000111000111100 question (x>3)&(x-y>1)
OK 000000000000000000000000111000111100 orlp0 x>3&x-y>1
OK 000000000000000000000000111000111100 orlp2 ~y+x>2>>y
OK 000000000000000000000000111000111100 orlp3 x*x-y*y>9
OK 000000000000000000000000111000111100 orlp4 ~y>x/~3*x
OK 000000000000000000000000111000111100 orlp5 -3>>y>y-x
OK 000000000000000000000000111000111100 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
static void driver<T>::run() [with T = long int]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
OK 000000000000000000000000111000111100 question (x>3)&(x-y>1)
OK 000000000000000000000000111000111100 orlp0 x>3&x-y>1
OK 000000000000000000000000111000111100 orlp2 ~y+x>2>>y
OK 000000000000000000000000111000111100 orlp3 x*x-y*y>9
OK 000000000000000000000000111000111100 orlp4 ~y>x/~3*x
OK 000000000000000000000000111000111100 orlp5 -3>>y>y-x
OK 000000000000000000000000111000111100 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
static void driver<T>::run() [with T = unsigned char]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
OK 000000000000000000000000111000111100 question (x>3)&(x-y>1)
OK 000000000000000000000000111000111100 orlp0 x>3&x-y>1
OK 000000000000000000000000111000111100 orlp2 ~y+x>2>>y
OK 000000000000000000000000111000111100 orlp3 x*x-y*y>9
OK 000000000000000000000000111000111100 orlp4 ~y>x/~3*x
OK 000000000000000000000000111000111100 orlp5 -3>>y>y-x
OK 000000000000000000000000111000111100 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
static void driver<T>::run() [with T = short unsigned int]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
OK 000000000000000000000000111000111100 question (x>3)&(x-y>1)
OK 000000000000000000000000111000111100 orlp0 x>3&x-y>1
OK 000000000000000000000000111000111100 orlp2 ~y+x>2>>y
OK 000000000000000000000000111000111100 orlp3 x*x-y*y>9
OK 000000000000000000000000111000111100 orlp4 ~y>x/~3*x
OK 000000000000000000000000111000111100 orlp5 -3>>y>y-x
OK 000000000000000000000000111000111100 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
static void driver<T>::run() [with T = unsigned int]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
ERR 000000000000000000000000111001111100 question (x>3)&(x-y>1)
ERR 000000000000000000000000111001111100 orlp0 x>3&x-y>1
ERR 111111011111001111000111111011111101 orlp2 ~y+x>2>>y
ERR 011111001111000111000011111001111100 orlp3 x*x-y*y>9
ERR 111111111111111111111111111111111111 orlp4 ~y>x/~3*x
ERR 111111011111001111000111111011111101 orlp5 -3>>y>y-x
ERR 111111011111001111000111111011111101 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
static void driver<T>::run() [with T = long unsigned int]
OK 000000000000000000000000111000111100 MASTER (x>3) && (x>y+1)
OK 000000000000000000000000111000111100 GOLF x>3&x>y+1
OK 000000000000000000000000111000111100 lookup "000000000000000000000000111000111100"[x*6+y]-'0'
ERR 000000000000000000000000111001111100 question (x>3)&(x-y>1)
ERR 000000000000000000000000111001111100 orlp0 x>3&x-y>1
ERR 111111011111001111000111111011111101 orlp2 ~y+x>2>>y
ERR 011111001111000111000011111001111100 orlp3 x*x-y*y>9
ERR 111111111111111111111111111111111111 orlp4 ~y>x/~3*x
ERR 111111011111001111000111111011111101 orlp5 -3>>y>y-x
ERR 111111011111001111000111111011111101 orlp6 ~y+x<<y>2
ERR 000000000000000000000000000000000000 orlp1 -x<~y>4>x
सारांश
चूंकि स्रोत कोड तत्वों को दोहराने की "लागत" के बारे में, आप एक लुकअप तालिका का उपयोग कर सकते हैं। आप लुकअप तालिका को "छिपा" सकते हैं, इसलिए यह या तो है
LUT[x][y]
या
LUT[x*6+y]
बेशक आप पांडित्यपूर्ण हो सकते हैं और LUT का नाम बदल सकते हैं
L[x][y]
तो मेरा "संस्करण" है ... 7 वर्ण । (या यदि कोई फ़ंक्शन है और L(x,y)इससे भी छोटा है)।
या, अधिक महत्वपूर्ण बात: सही, परीक्षण योग्य और बनाए रखने योग्य।