Compilare: user.cpp: In function ‘int main()’: user.cpp:19:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sir4.in","r",stdin); ^ user.cpp:20:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sir4.out","w",stdout); ^ user.cpp:22:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d %d ",&x,&a,&b,&m,&q); ^ user.cpp:32:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s+1); int l=strlen(s+1); int rest=0; ^ /tmp/ccOCIkyX.o: In function `main': user.cpp:(.text.startup+0x118): warning: the `gets' function is dangerous and should not be used.