Compilare: user.cpp: In function ‘void decoder()’: user.cpp:35:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<lv[k].size(); i++) ^ user.cpp:39:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int f=0; f<lv[k][i]->fin.size(); f++) ^ user.cpp: In function ‘void make_fail()’: user.cpp:83:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<lv[k].size(); i++) ^ user.cpp: In function ‘int main()’: user.cpp:133:18: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(v,Q,in); ^ user.cpp:137:25: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d\n",&n); ^ user.cpp:141:22: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(c,W,in); ^