Why is this function overloaded with an error in C ++?

Question

#include <iostream> int min(int a, int b){ return a < b ? a : b; } long long min(long long a, long long b){ return a < b ? a : b; } int main(){ int a = 1; long long b = 2; std::cout<<min(a, b); return 0; } 

Compilation Error:

test.cpp: In the function 'int main (): test.cpp: 15: 19: error: calling overloaded' min (int &, long long int &) is ambiguous sob <

But why is not long long min(long long a, long long b) not displayed automatically?

Does auto casting int a to long long a not degrade quality?

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 #include <iostream> long long min(long long a, long long b){ return a < b ? a : b; } int main(){ int a = 1; long long b = 2; std::cout<<min(a, b); return 0; } 

This one will work without error compilation.

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 #include <iostream> #include <algorithm> #include <functional> int main(){ int a = 1; long long b = 2; std::cout<<std::min(a, b); return 0; } 

In the file included in / usr / include / c ++ / 4.8 / algorithm: 62: 0, from test.cpp: 2: / usr / include / c ++ / 4.8 / bits / stl_algo.h: 4226: 5: note: template _Tp std :: min (std :: initializer_list <_Tp> _Compare) min (initializer_list <_Tp> __l, _Compare __comp) ^ / usr / include / c ++ / 4.8 / bits / stl_algo.h: 4226: 5: note: failure template / replacement argument: test.cpp: 8: 29: note:
mismatched types 'std :: initializer_list <_Tp> and' int std :: soy <