1: //textfile_io.cpp
2: //Illustrates C++ input from a file and output to a file.
4: #include <iostream>
5: #include <fstream>
6: using namespace std;
8: int main()
9: {
10: cout << "\nThis program reads data from a textfile called "
11: "\"in_data\", and writes it out\nto another textfile called "
12: "\"out_data\". The file in_data must be present.\n";
13: cout << "Press Enter to continue ... "; cin.ignore(80, '\n');
15: ifstream inFile; //Declare a file variable for input
16: ofstream outFile; //Declare a file variable for output
17: inFile.open("in_data"); //Connect "inFile" to a physical file
18: outFile.open("out_data"); //Connect "outFile" to a physical file
20: int i1, i2, i3, i4, i5, i6;
21: char c1, c2, c3, c4, c5, c6;
22: double r1, r2, r3, r4, r5, r6;
24: inFile >> i1 >> i2 >> i3;
25: inFile >> c1 >> c2 >> c3;
26: inFile >> r1 >> r2 >> r3;
27: inFile >> i4 >> i5 >> i6;
28: inFile.get(c4);
29: inFile.get(c5);
30: inFile.get(c6);
31: inFile >> r4 >> r5 >> r6;
32: inFile.close(); //Close the input file
34: outFile << "\nHere are the eighteen values read in, with a "
35: "\"<<\" marker\nat the end of each output line:\n";
36: outFile << "i1: " << i1
37: << "\t\t\ti2: " << i2
38: << "\t\t\ti3: " << i3 << "<<";
39: outFile << "\nc1: " << c1 << "<<"
40: << "\nc2: " << c2 << "<<"
41: << "\nc3: " << c3 << "<<\n";
42: outFile << "r1: " << r1 << "\t\tr2: "
43: << r2 << "\t\tr3: "
44: << r3 << "<<\n";
45: outFile << "i4: " << i4
46: << "\t\t\ti5: " << i5
47: << "\t\t\ti6: " << i6 << "<<";
48: outFile << "\nc4: " << c4 << "<<"
49: << "\nc5: " << c5 << "<<"
50: << "\nc6: " << c6 << "<<\n";
51: outFile << "r4: " << r4
52: << "\t\t\tr5: " << r5
53: << "\t\t\tr6: " << r6 << "<<\n";
54: outFile << endl;
55: outFile.close(); //Close the output file
57: cout << "\nIf all went well, the input file has been read, and "
58: "the output file has been\nwritten. However, you should, of "
59: "course, check to be sure.\n";
60: cout << "Press Enter to continue ... "; cin.ignore(80, '\n');
61: }