void CmnbDlg::OnBnClickedOk()
{main()
{
    FILE *fp
    char ch
    if((fp=fopen(“d:\\z.txt”，"r"))==NULL)
    {
        printf("cannot open the file:z.txt\n");
        exit();
    }
    while(feof(fp)==0)
    {
        ch=fgetc(fp);
        putchar(ch);
    }
    printf("\n");
    fclose(fp);
    // TODO: Add your control notification handler code here
    OnOK();
}