Compilare: user.cpp: In function ‘bool f(int)’: user.cpp:39:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(len > v[i].size()) return false; ^ user.cpp:47:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = len; j < v[i].size(); j++){ ^ user.cpp:55:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(len > v[i].size()) return false; ^ user.cpp:67:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = len; j < v[i].size(); j++){ ^ user.cpp: In function ‘int main()’: user.cpp:84:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d", &n); ^