Compilare: user.cpp: In function ‘char nextch()’: user.cpp:16:58: 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; ^ user.cpp: In function ‘int main()’: user.cpp:136:19: warning: ‘b’ may be used uninitialized in this function [-Wmaybe-uninitialized] left=b; ^ user.cpp:137:20: warning: ‘c’ may be used uninitialized in this function [-Wmaybe-uninitialized] right=c; ^