Compilare: user.cpp: In function ‘void reduce()’: user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp:43: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:93: warning: comparison between signed and unsigned integer expressions user.cpp:64: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:65: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:67: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:70: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:78: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result