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POerror C2783 Could not deduce template arguments
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  1. POerror C2783 Could not deduce template arguments
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    copied!<p>I am stuck with this error . <strong>I have found a workaround too but it kind of kills the whole purpose of exercise.</strong></p> <p>I am trying to create a function which will take two iterators pointing to same container . I will find the sum of elements between them. I created general function for the sequential containers like vector which works fine. I overloaded the same function for associative containers. This is the one giving error.</p> <pre><code>map&lt;string,double&gt; myMap; myMap["B"]=1.0; myMap["C"]=2.0; myMap["S"]=3.0; myMap["G"]=4.0; myMap["P"]=5.0; map&lt;string,double&gt;::const_iterator iter1=myMap.begin(); map&lt;string,double&gt;::const_iterator iter2=myMap.end(); cout&lt;&lt;"\nSum of map using the iterator specified range is: "&lt;&lt;Sum(iter1,iter2)&lt;&lt;"\n"; //Above line giving error. Intellisense is saying: Sum, Error: no instance of overloaded function "Sum" matches the argument list. //function to calculate the sum is listed below (It appears in a header file with &lt;map&gt; header included): template &lt;typename T1,typename T2&gt; double Sum(const typename std::map&lt;T1,T2&gt;::const_iterator&amp; input_begin,const typename std::map&lt;T1,T2&gt;::const_iterator&amp; input_end) { double finalSum=0; typename std::map&lt;T1,T2&gt;::const_iterator iter=input_begin; for(iter; iter!=input_end; ++iter) { finalSum=finalSum+ (iter)-&gt;second; } return finalSum; } </code></pre> <p>Compilation error is: 1>c:\documents and settings\ABC\my documents\visual studio 2010\projects\demo.cpp(41): error C2783: 'double Sum(const std::map::const_iterator &amp;,const std::map::const_iterator &amp;)' : could not deduce template argument for 'T1'</p> <p><strong>Workaround:</strong></p> <p>If call Sum(iter1,iter2) is replaced with Sum &lt; string,double > (iter1,iter2), it compiles fine. </p> <p>Was I trying to do something impossible as per C++ standards in the first place?</p>
 

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