c语言文件读写的问题，为什么读出的字节会变长

对txt文件按字节读取 每次读8个字节

问什么会出现这种情况 ，怎么解决，每次要读个字节

(https://img-ask.csdn.net/upload/201604/08/1460115662_349775.png)

 void PlayDesByFile(char *source,char*dest)
{   int time=0,i=0;
    long filelength;
    FILE *s,*d;
    char sbuffer[20]={0},dbuffer[8]={0};
    int count;
    if((s=fopen(source,"r+"))==NULL){
        printf("11111");
        return;

    }
    if((d=fopen(dest,"w+"))==NULL){
        printf("22222");
        return;
    }
    fseek(s,0,SEEK_END);
    filelength=ftell(s);
    rewind(s);
    while(!feof(s)){
            fread(sbuffer,1,8,s);
            i++;
          //  PlayDes(dbuffer,sbuffer);
            fwrite(sbuffer,1,8,d);
}

文件1. txt内容为abcdefgh
输出的2.txt为abcdefghabcde