编写程序，完成文件复制功能。

bool CopyFile(const char *src, const char *des)
{
    FILE * fSrc = fopen(src, "rb");
    if(!fSrc)
    {
        printf("打开文件`%s`失败", src);
        return false;
    }
    FILE * fDes = fopen(des, "wb");
    if(!fDes)
    {
        printf("创建文件`%s`失败", des);
        return false;
    }
    unsigned char * buf;
    unsigned int length;
    fseek(fSrc, 0, SEEK_END);
    length = ftell(fSrc);
    buf = new unsigned char[length+1];
    memset(buf, 0, length+1);
    fseek(fSrc, 0, SEEK_SET);
    fread(buf, length, 1, fSrc);
    fwrite(buf, length, 1, fDes);
    fclose(fSrc);
    fclose(fDes);
    delete [] buf;
    return true;
}
int main()
{
    char src[260] = { 0 };
    char des[260] = { 0 };
    printf("输入原文件名:");
    scanf("%s", &src);
    printf("输入目标文件名:");
    scanf("%s", &des);
    if(CopyFile(src, des))
        printf("文件复制成功");
    else
        printf("文件复制失败");
    return 0;
}