Compilare: user.cpp: In function ‘int main()’: user.cpp:63:15: warning: unused variable ‘dx’ [-Wunused-variable] const int dx[4] = {0, 0, 1, -1}; ^ user.cpp:64:15: warning: unused variable ‘dy’ [-Wunused-variable] const int dy[4] = {1, -1, 0, 0}; ^ user.cpp:72:15: warning: unused variable ‘st’ [-Wunused-variable] int a, b, st = 1, dr = 0; ^ user.cpp:80:9: warning: unused variable ‘nx’ [-Wunused-variable] int nx, ny; ^ user.cpp:80:13: warning: unused variable ‘ny’ [-Wunused-variable] int nx, ny; ^ user.cpp:109:9: warning: unused variable ‘dif_max’ [-Wunused-variable] int dif_max = -3 * NMAX; ^ user.cpp:110:9: warning: unused variable ‘dif_min’ [-Wunused-variable] int dif_min = 3 * NMAX; ^ user.cpp:111:9: warning: unused variable ‘sum_max’ [-Wunused-variable] int sum_max = -3 * NMAX; ^ user.cpp:112:9: warning: unused variable ‘sum_min’ [-Wunused-variable] int sum_min = 3 * NMAX; ^ user.cpp:113:9: warning: unused variable ‘aux’ [-Wunused-variable] int aux; ^ user.cpp: In constructor ‘InputReader::InputReader(const char*)’: user.cpp:15:47: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^ user.cpp: In member function ‘void InputReader::advance()’: user.cpp:37:51: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buffer, SIZE, 1, input_file); ^