ex56.c

c51学习的好书！

    #include<stdio.h>
    char code daytab[2][13]=
     {
      {0,31,28,31,30,31,30,31,31,30,31,30,31},
      {0,31,29,31,30,31,30,31,31,30,31,30,31}
     };

     char * mname(int n)  {
       char code *mn[]=
       {
         "Illigal month", "January", "February",
         "March", "April", "May", "June",
	     "July", "August", "September",
         "October", "Novenmber", "December"
        };
        return((n<1||n>12)? mn[0]: mn[n]);
      }

    monthday(int y, int yd)  {
      int i, leap;
      leap=y%4==0&&y%100!=0||y%400==0;
      for(i=1; yd>daytab[leap][i]; i++)
      yd-=daytab[leap][i];
      printf("%s, %d\n", mname(i), yd);
    }

    main()  {
      int year, yearday;
      printf("Input year and yearday: \n");
      scanf("%d, %d", &year, &yearday);
      monthday(year, yearday);
    }