Compilare: user.cpp: In function ‘unsigned int getdif(unsigned int, unsigned int, unsigned int, unsigned int)’: user.cpp:84:18: warning: unused variable ‘diff’ [-Wunused-variable] unsigned int diff[] = {a, b, c, d}; ^ user.cpp: In function ‘int main()’: user.cpp:108:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(unsigned int i = 1;(1 << i) <= nr;i++) ^ user.cpp:95:28: warning: unused variable ‘st’ [-Wunused-variable] unsigned int x, y;bool st = 0; ^ user.cpp: In function ‘char next()’: user.cpp:17:41: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, 1, BUF, fin), pos = 0; ^