Compilare: user.cpp: In function ‘int main()’: user.cpp:51:6: warning: unused variable ‘f1’ [-Wunused-variable] int f1, f2, f3; ^ user.cpp:51:10: warning: unused variable ‘f2’ [-Wunused-variable] int f1, f2, f3; ^ user.cpp:51:14: warning: unused variable ‘f3’ [-Wunused-variable] int f1, f2, f3; ^ user.cpp:47:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abcacm.in", "r", stdin); ^ user.cpp:48:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("abcacm.out", "w", stdout); ^ user.cpp:58:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &T); ^ user.cpp:63:52: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d%d%d", mat + 1, mat, mat + 2, &i); ^