Compilare: user.cpp: In function ‘int main()’: user.cpp:34:43: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d%d%d", &x, &y, &n, &l); ^ user.cpp:42:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &a); ^ user.cpp:84:17: warning: ‘ys’ may be used uninitialized in this function [-Wmaybe-uninitialized] dfs(xs,ys,1); ^ user.cpp:84:17: warning: ‘xs’ may be used uninitialized in this function [-Wmaybe-uninitialized]