Compilare: user.cpp: In function ‘int main()’: user.cpp:58:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int y = 0; y < E.size(); y++) ^ user.cpp:49:9: warning: unused variable ‘n’ [-Wunused-variable] int n = nextnum(), m = nextnum(); ^ user.cpp: In function ‘char nextch()’: user.cpp:11:36: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, BUF_SIZE, 1, fi); ^