c++ - How to check whether STL iterator points at anything? -


संभव डुप्लिकेट:

मैं इस तरह से कुछ करना चाहता हूं:

<पूर्व> std :: vector & lt; int & gt; :: iterator; // / / कट / वेक्टर में कुछ के लिए खोज और बिंदु iterator उस पर। अगर (! यह) // जांचें कि क्या मिलेगा do_something ();

लेकिन कोई ऑपरेटर नहीं है! आईटरेटर के लिए मैं जांच कैसे कर सकता हूं कि क्या किसी भी बात पर इटरेटर अंक है?

आप नहीं कर सकते हमेशा की मुहावरे कंटेनर के एंड इटरेटर का उपयोग करने के लिए है 'मार्क्स नहीं मिला' मार्कर यह वही है जो std :: find देता है। 

  std :: vector & lt; int & gt; :: iterator i = std :: find (v.begin (), v .end (), 13); अगर (i! = V.end ()) {// ...}

केवल एक चीज जो आप एक अनअसाइंड इटरेटर के साथ कर सकते हैं, उसके लिए एक मान असाइन कर रहा है।


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