One line reads a text file

The following is an example. It reads the first line of autoexec. bat.
# Include <stdio. h>
# Include <stdlib. h>

Main ()
{
File * FP;
CharS [256];
If(FP = fopen ("C: // autoexec. Bat", "R") = NULL)
{
Printf ("can't open file/N ");
Return;
}
Fgets (S, 256, FP );
Printf ("line1: % s/n", S );
Fclose (FP );
}
// The combination of file stream and string is the best:
# Include <iostream>
# Include <fstream>
# Include <strstream>
# Include <string>
Using namespaceSTD;

IntMain ()
{
String line;
Ifstream input ("input.txt", IOS: In );
Strstream temp;

While(1)
{
Getline (input, line );
If(Input. EOF ()) Break;
// A row of data has been stored in line and can be processed. Here, it is only output
Cout <line <Endl;
}
Input. Close ();

Return0;
}
Use get () and put ()

# Include <fstream. h>
Void main ()
{
Fstream file ("test_file.txt", IOS: Out | IOs: In | IOs: Binary );
Char ch;
Ch = 'O ';
File. Put (CH); // write ch content to the file
File. seekg (IOs: Beg); // locate the file header
File. Get (CH); // read one character
Cout <ch <Endl; // display it on the screen
File. Close ();
}
Use read () and write ()

# Include <fstream. h>
# Include <string. h>

Void main ()
{
Fstream file ("test_file.txt", IOS: Out | IOs: In | IOs: Binary );
File. Write (ARR, 5); // write the first five characters -- "hello" to the file.
File. seekg (IOs: Beg); // locate the file header
Static char read_array [100000], readone [1]; // here I will read some data
Int I = 0;
Do
{
File. Read (readone, 1); // read 1 Character
If (readone [0] ='s ')
{
...
}
I ++;
}
File. Close ();
}