edit: thank answers! said, code provided class, namespace , name of function included. i'm glad understand namespace std entails though, , i've included inputs comments within answer (though answer remains unchanged).
the code below includes piece created. class, only part need judged. compiler isn't running (ambiguous calls overloaded function) feel correct.
template <class data_type> void swap(data_type &a, data_type &b) //swaps 2 variables { data_type c; //temp variable c = a; = b; b = c; } here full code:
#include <iostream> #include <string> using namespace std; template <class data_type> void swap(data_type &a, data_type &b) //swaps variables { data_type c; c = a; = b; b = c; } int main( ) { string x = "first", y = "second"; int m = 10, n = 20; char q = 'q', r = 'r'; cout<<"x before swap called = "<<x<<" , y before swap called = " <<y<<endl; swap(x,y); cout<<"x after swap called = "<<x<<" , y after swap called = " <<y<<endl<<endl; cout<<"m before swap called = "<<m<<" , n before swap called = " <<n<<endl; swap(m,n); cout<<"m after swap called = "<<m<<" , n after swap called = " <<n<<endl<<endl; cout<<"q before swap called = "<<q<<" , r before swap called = " <<r<<endl; swap(q,r); cout<<"q after swap called = "<<q<<" , r after swap called = " <<r<<endl<<endl; return 0; }
the standard library comes template std::swap (see cpp reference), , defining own swap-template function. far no problem, once declare using namespace std, use of swap ambiguous, since compiler cannot decide whether take std::swap or own swap.
so, mentioned others, avoid using namespace std statement.
additionally, think of declaring "your" swap in own namespace, like:
namespace class1_exercise { template <class data_type> void swap(data_type &a, data_type &b) //swaps variables { data_type c; c = a; = b; b = c; } } thereby, can make distinction between "your" swap , std::swap more explicit:
std::swap(x,y); // versus: class1_exercise::swap(x,y); 
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