Compilare: user.cpp: In function ‘int pair_up(int)’: user.cpp:17: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void markR(int, int)’: user.cpp:33: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void markL(int, int)’: user.cpp:42: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:77: warning: comparison between signed and unsigned integer expressions user.cpp:48: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:49: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:56: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result