建立文件输出

文件输出步骤总结：

1、建立输出流对象，并将输出流对象和输出文件名绑定：ofstream sss_out("sssout.txt");

2、向输出流输出元素，有两种方式，一种是直接输出：sss_out<<输出内容；

 1 // Fig. 14.3: fig14_03.cpp
 2 // Create a sequential file.
 3 #include <iostream>
 4 #include <string>
 5 #include <fstream> // contains file stream processing types
 6 #include <cstdlib> // exit function prototype
 7 using namespace std;
 8 
 9 int main()
10 {
11                 
12     ofstream sss_out("sssout.txt");// 建立输出流sss_out，并将输出流和文件sssout.txt绑定
13 
14     // exit program if unable to create file
15     if (!sss_out) // overloaded ! operator
16     {
17         cerr << "File could not be opened" << endl;
18         exit(EXIT_FAILURE);
19     } // end if
20 
21     cout << "Enter the account, name, and balance." << endl
22         << "Enter end-of-file to end input.
? ";
23 
24     int account; // the account number
25     string name; // the account owner's name
26     double balance; // the account balance
27 
28     // read account, name and balance from cin, then place in file
29     while (cin >> account >> name >> balance)
30     {
31         sss_out << account << ' ' << name << ' ' << balance << endl;//向输出流输出元素
32         cout << "? ";
33     } // end while
34 } // end main

另一种可以建立输出流迭代器进行输出： ostream_iterator<int> out(out_xls," sss ");//sss为每个元素输出后输出的内容，即间隔。

 1 #include<iostream>
 2 #include<fstream>
 3 #include<iterator>
 4 using namespace std;
 5 
 6 int main() {
 7     ofstream out_xls("int.txt");
 8     //istream_iterator<int> in(cin);
 9     ostream_iterator<int> out(out_xls," sss ");
10     int i;
11     while (cin >> i) {
12         *out++ = i;
13     }
14 
15 }