File Input / Output

Is written to a text file

 

Text I / O cout

It must include the header file iostream

Ostream iostream header file defines processing for outputting a class of

iostream declares a variable named cout of ostream (Object)

You must specify the namespace std;

And operators can be used cout << binding to display various types of data.

 

File I / O similar thereto

It must include the header file fstream

Ofstream fstream header file defines a class for processing output.

Ofstream need to declare one or more variables (objects), and the way you like to be named.

You must specify the namespace std;

We need to associate it with a file ofstream objects. open () method.

After finished with the file, the method should be used close () to close it.

Use ofstream objects and operator << outputs various types of data may be combined.

 

Although the header file iostream provides a predefined named cout is an ostream object, but must declare their ofstream objects, give it a name and associate it with the file.

 

// declare an object 
ofstream the outFile; 
ofstream FOUT; 

// object associated with a particular file 
outFile.open ( " fish.txt " );
 char filename [ 50 ]; 
cin >> filename; 
fout.open (filename);

 

The method open () accepts a C-style string as a parameter, which may be a literal string, or a string stored in the array.

//此种对象的使用方法
double wt=125.8；
outFile <<wt;
char line[81]="Objects are closer than they appear.";
fout<<line<<endl;

In short, after declaring a ofstream objects and their associated Tong files, you can use it to use as cou. Cout for all the operations and methods (e.g., <<, endl, setf ()) may be used ofstream objects.

Summarizes the main steps:

1. include the header file fstream.

2. Create a ofstream object.

3. The ofstream object is associated with a file up.

4. As with cout like to use the ofstream object.

#include <the iostream> 
#include <the fstream>                  // header file containing the fstream 
the using  namespace STD; 

int main () 
{ 
    char Automobile [ 50 ];     // character arrays, for storing car brands and models 
    int year;              // production Year 
    Double a_price;         // cost price 
    Double d_price;         // discount 
    ofstream the outFile;                   // define a file output stream object the outFile
     // after you define a file stream object, you can use the member functions need to open the file open operation
     //Open void (const unsigned char * filename, the MODE int, int Access = filebuf: openprot);
     // filename is character pointer, specify the name of the file you want to open
     // the MODE specifies the file is opened (ostream default ios :: OUT | ios :: trunc)
     // Access the specified file system properties, and generally the default 

    outFile.open ( " carinfo.txt " , ios :: OUT | ios :: trunc); 
    cout << " enter the make and model of car: : " ;      
    cin.getline (Automobile, 50 ); 
    COUT << " enter the year: " ; 
    CIN >> year; 
    COUT << " input cost:" ; 
    CIN >> a_price; 
    d_price = 0.913 * a_price; 
    cout << Fixed ;                      // output float usual way 
    cout.precision ( 2 );                  // set with an accuracy of 2, and return to the previous settings 
    cout .setf (ios_base :: showpoint);    // display float zero behind the decimal point.
     // output on screen 
    cout << " the Make and Model: " << Automobile << endl; 
    cout << " year: " << year << endl;
    cost<< "Was asking $" << a_price << endl;
    cout << "Now asking $" << d_price << endl;

    outFile << fixed;
    outFile.precision(2);
    outFile.setf(ios_base::showpoint);
    //输出到文件，类似于cout,将右边的输入到文件中
    outFile<< "Make and model:" << automobile << endl;
    outFile << "year:" << year << endl;
    outFile<< "Was asking $" << a_price << endl;
    outFile<< "Now asking $" << d_price << endl;
    //使用完毕，clos关闭
    outFile.close();
    return 0;

}