Compilare: user.cpp: In function ‘int main()’: user.cpp:17:13: warning: unused variable ‘j’ [-Wunused-variable] int n,i,j; ^ user.cpp:15:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paranteze2.in","r",stdin); ^ user.cpp:16:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("paranteze2.out","w",stdout); ^ user.cpp:18:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s+1); ^ /tmp/cc4W2pOY.o: In function `main': user.cpp:(.text.startup+0x56): warning: the `gets' function is dangerous and should not be used.