Compilare: user.cpp: In function ‘int main()’: user.cpp:156:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 0; k < trees.size(); k++) ^ user.cpp:27:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi, "%d %d\n", &l, &c); ^ user.cpp:30:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi, "%s\n", s); ^ user.cpp:146:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi, "%d\n", &n); ^ user.cpp:150:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi, "%d %d\n", &x, &y); ^