How to read and write files in C ++ Builder

When programming in C ++, code file operations are a common problem. In C ++ Builder, you can use multiple methods to operate files, in C ++ Builder, we will introduce this in detail in the following sections. The following will be a one-to-one list:

1. C-based file operations;

2. File Operations Based on C ++;

3. WINAPI-based file operations;

4. File Operations Based on the BCB library;

5. Special file operations.

In ANSIC, file operations are divided into two methods: stream file operations and I/O file operations, which are described below.

1) stream File Operations

This FILE operation has an important structure FILE, which is defined in stdio. h as follows:

 
 

  
  
typedef struct {   
  
  
int level; /* fill/empty level of buffer */   
  
  
unsigned flags; /* File status flags */   
  
  
char fd; /* File descriptor */   
  
  
unsigned char hold; /* Ungetc char if no buffer */   
  
  
int bsize; /* Buffer size */   
  
  
unsigned char _FAR *buffer; /* Data transfer buffer */   
  
  
unsigned char _FAR *curp; /* Current active pointer */   
  
  
unsigned istemp; /* Temporary file indicator */   
  
  
short token; /* Used for validity checking */   
  
  
} FILE; /* This is the FILE object */ 
 
 

The C ++ Builder structure contains the basic attributes of file operations. Operations on files must be performed through the pointer of this structure. Common functions for such file operations are as follows:

 
 

  
  
Fopen () Open stream
  
  
 
  
  
Fclose () Close the stream
  
  
 
  
  
Fputc () writes a character to the stream
  
  
 
  
  
Fgetc () reads a character from the stream
  
  
 
  
  
Fseek () locates the specified character in the stream
  
  
 
  
  
Fputs () writes a string to a stream
  
  
 
  
  
Fgets () reads a row or a specified character from the stream.
  
  
 
  
  
Fprintf () Outputs Data to the stream in the format
  
  
 
  
  
Fscanf () reads data from the stream in the format
  
  
 
  
  
Returns the true value when feof () reaches the end of a file.
  
  
 
  
  
Returns the value of ferror () When an error occurs.
  
  
 
  
  
Rewind () resets the file locator to the beginning of the file
  
  
 
  
  
Remove () delete an object
  
  
 
  
  
Fread () reads a specified number of characters from a stream
  
  
 
  
  
Fwrite () writes a specified number of characters to the stream.
  
  
 
  
  
Tmpfile () generates a temporary file stream
  
  
 
  
  
Tmpnam () generates a unique file name
 
 

1. Introduction to C ++
2. Summary Notes on learning and exploring C ++ library functions
3. Basic Conception and method of C ++ Class Library Design
4. Does C ++ really have market value?
5. Basic Conception and method of C ++ Class Library Design