Compilare: user.cpp: In function ‘void merge_sort(long int, long int, long int)’: user.cpp:14: warning: suggest parentheses around comparison in operand of ‘&’ user.cpp:18: warning: suggest parentheses around comparison in operand of ‘&’ user.cpp: In function ‘int main()’: user.cpp:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result