C File fseek() Function

The fseek() function is used to set the file pointer to the specified offset. It is used to write data to the required position in the file.

Syntax:

int fseek(FILE　*stream, long int offset, int whence)

parameters

The first parameter stream is the file pointer
The second parameter offset is the offset, an integer represents positive offset, and a negative number represents negative offset
The third parameter whence sets where to start the offset, and can use3one of the constants, which may have values: SEEK_CUR, SEEK_END, or SEEK_SET
SEEK_SET　 -　 beginning of the file
SEEK_CUR　 -　 current position
SEEK_END　 -　 end of the file
Among them, SEEK_SET, SEEK_CUR, and SEEK_END can also be used in sequence as 0,1 and 2indicates.

Example

#include <stdio.h>　　
void main() {　　
　　　FILE　*fp;　　
　　
　　　fp = fopen("myfile.txt","w")+　　
　　　fputs("This is w"3codebox.com", fp);　　
　　　　
　　　fseek(fp,　7, SEEK_SET );　　
　　　fputs("Seagull Ali", fp);　　
　　　fclose(fp);　　
}

myfile.txt

This is Seagull Ali