#include<stdio.h>
#include<conio.h>
 
void main()
{struct
 {
  char seat;
 }a[19];
 int x,z;
 char y;
 a[0].seat='A';
 a[1].seat='B';
 a[2].seat='C';
 a[3].seat='D';
 a[4].seat='A';
 a[5].seat='B';
 a[6].seat='C';
 a[7].seat='D';
 a[8].seat='A';
 a[9].seat='B';
 a[10].seat='C';
 a[11].seat='D';
 a[12].seat='A';
 a[13].seat='B';
 a[14].seat='C';
 a[15].seat='D';
 a[16].seat='A';
 a[17].seat='B';
 a[18].seat='C';
 a[19].seat='D';
 clrscr();
 printf("Flight Seat Reservation:");
 printf("\n\n\n\t1\t%c\t%c\t%c\t%c", a[0].seat, a[1].seat, a[2].seat, a[3].seat);
 printf("\n\t2\t%c\t%c\t%c\t%c", a[4].seat, a[5].seat, a[6].seat, a[7].seat);
 printf("\n\t3\t%c\t%c\t%c\t%c", a[8].seat, a[9].seat, a[10].seat, a[11].seat);
 printf("\n\t4\t%c\t%c\t%c\t%c", a[12].seat, a[13].seat, a[14].seat, a[15].seat);
 printf("\n\t5\t%c\t%c\t%c\t%c", a[16].seat, a[17].seat, a[18].seat, a[19].seat);
 for(z=0;z<=20;++z)
 {printf("\n\nEnter your row number:\n");
  scanf("%d", &x);
  if(x==1||x==2||x==3||x==4||x==5)
    {printf("\n\nEnter your seat letter:\n");
     scanf("%s", &y);
      if(y!='a'&&y!='A'&&y!='b'&&y!='B'&&y!='c'&&y!='C'&&y!='d'&&y!='D')
       {printf("\n\nSorry, you have entered a wrong seat letter.");
	printf("\n\nPlease enter another seat letter: ");
	scanf("%s", &y);}}
  else
     {printf("\n\nSorry you have entered a wrong row number");
      printf("\n\nPlease enter seat number again: \n");
      scanf("%d", &x);
      printf("\n\nEnter your seat letter:\n");
      scanf("%s", &y);};
  if(x==1)
     {if(y=='a'||y=='A')
       a[0].seat='*';
      else if(y=='b'||y=='B')
       a[1].seat='*';
      else if(y=='c'||y=='C')
       a[2].seat='*';
      else if(y=='d'||y=='D')
       a[3].seat='*';}
   else if(x==2)
      {if(y=='a'||y=='A')
	a[4].seat='*';
       else if(y=='b'||y=='B')
	a[5].seat='*';
       else if(y=='c'||y=='C')
	a[6].seat='*';
       else if(y=='d'||y=='D')
	a[7].seat='*';}
   else if(x==3)
      {if(y=='a'||y=='A')
	a[8].seat='*';
       else if(y=='b'||y=='B')
	a[9].seat='*';
       else if(y=='c'||y=='C')
	a[10].seat='*';
       else if(y=='d'||y=='D')
	a[11].seat='*';}
   else if(x==4)
      {if(y=='a'||y=='A')
	a[12].seat='*';
       else if(y=='b'||y=='B')
	a[13].seat='*';
       else if(y=='c'||y=='C')
	a[14].seat='*';
       else if(y=='d'||y=='D')
	a[15].seat='*';}
   else if(x==5)
      {if(y=='a'||y=='A')
	a[16].seat='*';
       else if(y=='b'||y=='B')
	a[17].seat='*';
       else if(y=='c'||y=='C')
	a[18].seat='*';
       else if(y=='d'||y=='D')
	a[19].seat='*';}
   printf("Flight Seat Reservation:");
   printf("\n\n\n\t1\t%c\t%c\t%c\t%c", a[0].seat, a[1].seat, a[2].seat, a[3].seat);
   printf("\n\t2\t%c\t%c\t%c\t%c", a[4].seat, a[5].seat, a[6].seat, a[7].seat);
   printf("\n\t3\t%c\t%c\t%c\t%c", a[8].seat, a[9].seat, a[10].seat, a[11].seat);
   printf("\n\t4\t%c\t%c\t%c\t%c", a[12].seat, a[13].seat, a[14].seat, a[15].seat);
   printf("\n\t5\t%c\t%c\t%c\t%c", a[16].seat, a[17].seat, a[18].seat, a[19].seat);}
  getch();
  }

 if(y!='a'&&y!='A'&&y!='b'&&y!='B'&&y!='c'&&y!='C'&&y!='d'&&y!='D')
       {printf("\n\nSorry, you have entered a wrong seat letter.");
	printf("\n\nPlease enter another seat letter: ");
	scanf("%s", &y);}}