Compilare: user.cpp: In function ‘int main()’: user.cpp:21:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:23:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(S); ^ /tmp/cc4pdNIV.o: In function `main': user.cpp:(.text.startup+0x3d): warning: the `gets' function is dangerous and should not be used.