62 lines
1.6 KiB
C++
62 lines
1.6 KiB
C++
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//filefunc.cpp -- function with ostream & parameter
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#include <iostream>
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#include <fstream>
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#include <cstdlib>
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using namespace std;
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void file_it(ostream & os, double fo, const double fe[],int n);
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const int LIMIT = 5;
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int main()
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{
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ofstream fout;
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const char * fn = "ep-data.txt";
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fout.open(fn);
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if (!fout.is_open())
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{
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cout << "Can't open " << fn << ". Bye.\n";
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exit(EXIT_FAILURE);
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}
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double objective;
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cout << "Enter the focal length of your "
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"telescope objective in mm: ";
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cin >> objective;
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double eps[LIMIT];
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cout << "Enter the focal lengths, in mm, of " << LIMIT
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<< " eyepieces:\n";
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for (int i = 0; i < LIMIT; i++)
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{
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cout << "Eyepiece #" << i + 1 << ": ";
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cin >> eps[i];
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}
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file_it(fout, objective, eps, LIMIT);
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file_it(cout, objective, eps, LIMIT);
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cout << "Done\n";
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// cin.get();
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// cin.get();
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return 0;
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}
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void file_it(ostream & os, double fo, const double fe[],int n)
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{
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// save initial formatting state
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ios_base::fmtflags initial;
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initial = os.setf(ios_base::fixed, ios_base::floatfield);
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std::streamsize sz = os.precision(0);
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os << "Focal length of objective: " << fo << " mm\n";
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os.precision(1);
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os.width(12);
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os << "f.l. eyepiece";
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os.width(15);
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os << "magnification" << endl;
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for (int i = 0; i < n; i++)
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{
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os.width(12);
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os << fe[i];
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os.width(15);
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os << int (fo/fe[i] + 0.5) << endl;
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}
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// restore initial formatting state
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os.setf(initial, ios_base::floatfield);
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os.precision(sz);
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}
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