Compilare: user.cpp: In function ‘int main()’: user.cpp:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void Calc()’: user.cpp:113: warning: comparison between signed and unsigned integer expressions user.cpp:127: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void Calc2()’: user.cpp:159: warning: unused variable ‘e’