Compilare: user.cpp: In function ‘int main()’: user.cpp:65:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.in","r",stdin); ^ user.cpp:66:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("senat.out","w",stdout); ^ user.cpp:67:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n%d\n",&N,&M); ^ user.cpp:75:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(num); ^ /tmp/ccC8ggvG.o: In function `main': user.cpp:(.text.startup+0xba): warning: the `gets' function is dangerous and should not be used.