Compilare: user.cpp: In function ‘int main()’: user.cpp:47:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "cifra.in", "r" , stdin); ^ user.cpp:48:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "cifra.out" , "w", stdout); ^ user.cpp:50:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &t); ^ user.cpp:65:10: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(N); ^ /tmp/cc32N6p9.o: In function `main': user.cpp:(.text.startup+0x174): warning: the `gets' function is dangerous and should not be used.