Compilare: main.cpp: In function 'int main()': main.cpp:52:21: warning: unused variable 'j' [-Wunused-variable] int n, p, z, i, j, x ; ^ main.cpp: In member function 'void InputReader<T>::advance() [with T = int]': main.cpp:20:13: 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) ; ^~~~~ main.cpp: In constructor 'InputReader<T>::InputReader(const char*) [with T = int]': main.cpp:28:9: 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) ; ^~~~~