```c
void writeExcel(int a)                                                   /*Функция записи данных в Excel*/
{
	char *wday[] = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
	time_t timep;
    struct tm *p;
    time(&timep);
    p = gmtime(&timep);
  
    FILE *fp;  
    int t=0;  
    char ch;
	char d;

	t = a;
	if((fp = fopen("D:\\ѧϰλ��\\C++\\���ݼ�¼����.xls", "r")) == NULL)
	{
		fp = fopen("D:\\ѧϰλ��\\C++\\���ݼ�¼����.xls", "w");
	} 
	else
	{
		fp = fopen("D:\\ѧϰλ��\\C++\\���ݼ�¼����.xls", "a+");
	}
    fprintf(fp, " \n %04d\t %s\t ", t, (wday[p->tm_wday]));
	system("pause");
	system("cls");
	printf("\n\n\n");
	printf("                   Данные записаны успешно\n\n");
	fclose(fp);
}
```