Compilare: user.cpp: In function ‘int main()’: user.cpp:30:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( k = 0; k < L[j].size(); k++ ){ ^ user.cpp:41:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( i = 0; i < L[0].size() ; i++ ){ ^ user.cpp:16:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&n,&m); ^ user.cpp:18:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d%d",&a,&b,&c); ^