The C library function **`fseek()`** sets the file position of the stream to a given offset. The pointer associated with the file is moved to that offset.

# Syntax
The basic syntax of the function is:

`whence` defines the point with respect to where the file pointer needs to be moved. It is specified by one of the following constants:
- **SEEK_END**: End of the file.
- **SEEK_SET**: Beginning of the file.
- **SEEK_CUR**: Current position of the file pointer.​

# Code
The following code opens a text file and moves the pointer to the end of the file using the `SEEK_END` argument. It then moves the pointer three places ahead of the start of the file, using the `SEEK_SET` argument, and prints the remaining characters in the file.

#include <stdio.h> 
  
int main() 
{ 
    FILE *fp; 
    fp = fopen("file.txt", "r"); 
      
    // Moving pointer to end 
    fseek(fp, 0, SEEK_END); 
      
    // Printing position of pointer 
    printf("Current position of pointer: ");
    printf("%ld \n", ftell(fp)); 

    // Moving the pointer 3 places ahead 
    // of the start of the file
    fseek(fp,3,SEEK_SET);
    int c;
    printf("Bytes after the first 3 bytes: ");
    while( (c=fgetc(fp)) != EOF)
        putchar(c);

    return 0; 
} 

What is fseek() in C?

fseek() in C sets and moves the file pointer to a specified offset from a defined position.