Compilare: user.cpp: In function ‘void Calc()’: user.cpp:29:11: warning: unused variable ‘j’ [-Wunused-variable] int i,j,k; ^ user.cpp:29:13: warning: variable ‘k’ set but not used [-Wunused-but-set-variable] int i,j,k; ^ user.cpp: In function ‘int main()’: user.cpp:47:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("qxy.in","r",stdin); ^ user.cpp:48:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("qxy.out","w",stdout); ^ user.cpp:49:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&N); ^ user.cpp:51:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&a[i]); ^ user.cpp:55:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&q); ^ user.cpp:57:43: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d %d\n",&i,&j,&x,&y); ^