Compilare: user.cpp: In function ‘int main()’: user.cpp:39:12: warning: unused variable ‘x’ [-Wunused-variable] int n, x; ^ user.cpp: In function ‘char nextch()’: user.cpp:19:58: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(pos==BUF_SIZE) fread(buf, BUF_SIZE, 1, fin), pos=0; ^