Compilare: user.cpp: In function ‘void merge_sort(int*, int, int, int)’: user.cpp:29: warning: suggest parentheses around ‘-’ inside ‘<<’ user.cpp:30: warning: suggest parentheses around ‘-’ inside ‘<<’ user.cpp: In function ‘int main()’: user.cpp:49: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:50: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:52: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:54: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result