c语言中对文件修改后放入同一文件中

#include"stdio.h"
#include"stdlib.h"
#include"string.h"
#include"fcntl.h"

#define X 7
#define Y 128

#define FILE_OPEN_FAILED -1
#define SUCESS 1

int CopyData_From_Txt(char* from_file,int arr[][Y])
{
    int fd,read_size;
    int i,j,k=0;
    int MAX_SIZE=896;
    char* fbuff=(char*)malloc(MAX_SIZE);
    char* buff=fbuff;
    fd=open(from_file,O_RDWR,0777);
    if(fd==-1)
    {
        printf("The file of %s don't exist\n",from_file);
        return FILE_OPEN_FAILED;
    }
    while(read_size=read(fd,buff,MAX_SIZE)>0)
    printf("%s\n",buff);
    while(*buff++)
    {
        if(*buff==','){
            *buff=' ';
        }
        k++;
    }
    printf("%s\n",fbuff);
    lseek(fd,0,SEEK_SET);
    int n=write(fd,fbuff,k);
    free(fbuff);
    fbuff=NULL;
    buff=NULL;
    close(fd);
    return SUCESS;
}

int  main(int argc,char* argv[])
{
    //char* filename="./mouse10.txt";

    int arr[X][Y];
    if(argc==1)
    {
        printf("please input like this:\n ./a.out filename\n");
        return -1;
    }
    CopyData_From_Txt(argv[1],arr);

    return 0;
}
~