Compilare: user.cpp: In function ‘int main()’: user.cpp:42:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,N,sol=0; ^ user.cpp:43:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("dictree.in","r",stdin); ^ user.cpp:44:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("dictree.out","w",stdout); ^ user.cpp:45:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^ user.cpp:48:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s", (v[i].a+1)); ^