C++_Grocery

*******CLASSES*******
<iostream>
        cin, cout, flush, '\a', '\b', '\t', '\n', endl, >> (search ignoring whitespace, fetch until unmatched.), <<
<iomanip>
        setw(2), setprecision(16), setiosflags(ios::left/right/fixed), resetiosflags(ios::left/right/fixed)
<fstream>
        ofstream ofsname("filename"), ofsname<<"stream to write", ifstream ifsname("filename"), getline(ifsname,linestringread)
        , eof(), is_open();
<cmath>
        fabs(double d), sqrt(double d)
<ctime>
        time_t, time(NULL) => time_t, ctime(&t) => string formatted time, difftime(t1, t2) => integer seconds,
<string>
        st.find('\n') => index, string::npos, st.substr(0,5) => string, stringstream
<exception>
        class exception, exception.what()