c++ for loop temporary variable use -

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निम्न में से कौन सा बेहतर है और क्यों? (विशेषकर सी ++)

a। 

  int i (0), iMax (vec.length ()); // vec एक कंटेनर है, कहते हैं std :: वेक्टर के लिए (; i & lt; iMax; ++ i) {// लूप बॉडी}

b। 

  के लिए (int i (0); मैं & lt; ve.length (); ++ i) {// लूप बॉडी}

मैंने (ए) के लिए कॉलम की लंबाई फ़ंक्शन के लिए सलाह देखी है I यह मुझे परेशान कर रहा है क्या कोई भी आधुनिक संकलक (ए) के समान होने के लिए (बी) का अनुकूलन नहीं करता है?

उदाहरण (बी) के उदाहरण (ए) के लिए एक अलग अर्थ है, और जैसा कि आप इसे लिखते हैं, उसे संकलक के रूप में व्याख्या करना चाहिए।

यदि, (कुछ तैयार किए गए कारणों के लिए जो मैं नहीं सोच सकता है), मैंने ऐसा करने के लिए कोड लिखा था: (i), i push_back (विजेट ()); }

मैं वास्तव में संकलक को प्रत्येक कॉल को vec.length () से ऑप्टिमाइज़ करना नहीं चाहता होता, क्योंकि मुझे अलग-अलग परिणाम मिलेंगे।


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