Compilare: user.cpp: In function ‘int main()’: user.cpp:68:7: warning: variable ‘n’ set but not used [-Wunused-but-set-variable] int n, m, i, a, b, c = 0, t; ^ user.cpp: In function ‘char readch()’: user.cpp:16:26: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(s, BUFF, 1, in); ^