Compilare: user.cpp: In function ‘void read()’: user.cpp:9:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vecini2.in", "r", stdin); ^ user.cpp:10:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:11:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a + 1); ^ user.cpp:12:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(b + 1); ^ user.cpp: In function ‘void write()’: user.cpp:107:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vecini2.out", "w", stdout); ^ /tmp/cc3AblO2.o: In function `read()': user.cpp:(.text+0x44): warning: the `gets' function is dangerous and should not be used.