Compilare: user.cpp: In function ‘int main()’: user.cpp:34:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<L.size();i++){ ^ user.cpp:24:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:26:43: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&x[0][i],&x[1][i]); ^