Compilare: user.cpp: In function ‘void solve()’: user.cpp:34:15: warning: unused variable ‘j’ [-Wunused-variable] int i;int j;int n; ^ user.cpp:37:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n",c); ^ user.cpp: In function ‘int main()’: user.cpp:44:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("prefix.in","r",stdin); ^ user.cpp:45:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("prefix.out","w",stdout); ^ user.cpp:46:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t); ^