Compilare: user.cpp: In function ‘int main()’: user.cpp:62:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<st.size();i++) ^ user.cpp:40:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d %d",&n,&k); ^ user.cpp:43:33: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d %d",&x,&y); ^