Program to find the day of a week of a given date from 15 october 1582 to end of universe using arrays

 #include<iostream.h>
 #include<conio.h>


 int year_code(int,int);

 main()
    {
       clrscr();

       int date;
       int year;
       int month;
       int birth_week;
       int century;
       int birth_year;
       int century_remainder;
       int century_code;
       int birth_year_code;
       int day;

       cout<<"\n Enter the date in the following pattern :"<<endl;
       gotoxy(34,3);
       cout<<"Date - Month - Year"<<endl;

       gotoxy(39,4);
       cout<<"-       -       "<<endl;

       gotoxy(35,4);
       cin>>date;

       gotoxy(43,4);
       cin>>month;

       gotoxy(50,4);
       cin>>year;

       century=year/100;
       birth_year=year%100;

       century_remainder=century%4;

       if(century_remainder==0)
      century_code=date-1;

       elseif(century_remainder==1)
      century_code=date-3;

       elseif(century_remainder==2)
      century_code=date-5;

       else
      century_code=date;

       birth_year_code=year_code(birth_year,month);
       birth_week=century_code+birth_year_code;

       cout<<"\n The day on the given date is : ";

       day=birth_week%7;

       switch(day)
      {
         case 0: cout<<"Friday";
             break;

         case 1: cout<<"Saturday";
             break;

         case 2: cout<<"Sunday";
             break;

         case 3: cout<<"Monday";
             break;

         case 4: cout<<"Tuesday";
             break;

         case 5: cout<<"Wednesday";
             break;

         case 6: cout<<"Thursday";
             break;
      }

       getch();
       return 0;
    }

int year_code(int year,int month)
    {
       int code;

       int array_1[12]={3,6,6,2,4,7,2,5,1,3,6,1};
       int array_2[12]={4,7,7,3,5,1,3,6,2,4,7,2};
       int array_3[12]={5,1,1,4,6,2,4,7,3,5,1,3};
       int array_4[12]={6,2,3,6,1,4,6,2,5,7,3,5};
       int array_5[12]={1,4,4,7,2,5,7,3,6,1,4,6};
       int array_6[12]={2,5,5,1,3,6,1,4,7,2,5,7};
       int array_7[12]={3,6,6,2,4,7,2,5,1,3,6,1};
       int array_8[12]={4,7,1,4,6,2,4,7,3,5,1,3};
       int array_9[12]={6,2,2,5,7,3,5,1,4,6,2,4};
       int array_10[12]={7,3,3,6,1,4,6,2,5,7,3,5};
       int array_11[12]={2,3,1,2,4,7,2,5,1,3,6,1};
       int array_12[12]={7,3,4,7,2,5,7,3,6,1,4,6};
       int array_13[12]={5,1,2,5,7,3,5,1,4,6,2,4};
       int array_14[12]={3,6,7,3,5,1,3,6,2,4,7,2};
       int array_15[12]={1,4,5,1,3,6,1,4,7,2,5,7};

       if(year==1 || year==29 || year== 57 || year==85 || year==7 ||
     year==35 || year==63 || year==91 || year==18 || year==46 || year==74)
      code=array_1[month-1];

       elseif(year==2 || year==30 || year== 58 || year==86 || year==13 ||
     year==41 || year==69 || year==97 || year==19 || year==47 || year==75)
      code=array_2[month-1];

       elseif(year==3 || year==31 || year== 59 || year==87 || year==14 ||
     year==42 || year==70 || year==98 || year==25 || year==53 || year==81)
      code=array_3[month-1];

       elseif(year==4 || year==32 || year== 60 || year==88)
      code=array_4[month-12];

       elseif(year==5 || year==33 || year== 61 || year==89 || year==11 ||
     year==39 || year==67 || year==95 || year==22 || year==50 || year==78)
      code=array_5[month-1];

       elseif(year==6 || year==34 || year== 62 || year==90 || year==17 ||
             year==45 || year==73 || year==23 || year==51 || year==79)
      code=array_6[month-1];

       elseif(year==7 || year==35 || year== 63 || year==91)
      code=array_7[month-1];

       elseif(year==8 || year==36 || year==64 || year==92)
      code=array_8[month-1];

       elseif(year==9 || year==37 || year== 65 || year==93 || year==15 ||
     year==43 || year==71 || year==99 || year==26 || year==54 || year==82)
      code=array_9[month-1];

       elseif(year==10 || year==38 || year==66 || year==94 || year==21 ||
             year==49 || year==77 || year==27 || year==55 || year==83)
      code=array_10[month-1];

       elseif(year==12 || year==40 || year==68 || year==96)
      code=array_11[month-1];

       elseif(year==16 || year==44 || year==72 || year==100)
      code=array_12[month-1];

       elseif(year==20 || year==48 || year==76)
      code=array_13[month-1];

       elseif(year==24 || year==52 || year==80)
      code=array_14[month-1];

       elseif(year==28 || year==56 || year==84)
      code=array_15[month-1];

       return code;
    }