Compilare: user.cpp: In function ‘char nextch()’: user.cpp:12:33: 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, MAXBUF, fi); ^ user.cpp: In function ‘int main()’: user.cpp:88:144: warning: ‘col’ may be used uninitialized in this function [-Wmaybe-uninitialized] ans = std::max(ans, ((check(stk.top().h) + 1) * (stk.top().l + l - ((stk.top().col - stk.top().l + 1) % 2 == 0) - (col % 2 == 0) + 1)) / 4); ^