Thread: Need help with a switch statement

I'm writing a program that lets a user look at and alter the manifest of a small plane. My functions are working properly but when I go through the switch statement it runs through it one more time than I need it to.

Here is my code:

Code:

#include "stdafx.h"
#include "string.h"

#define maxSeats 12
#define nameLength 25
 
char menuDisplay (void);
int emptySeats (void);
void listEmpty (void);
void assignSeat (void);
void deleteSeat (void);

struct seatInformation
{	unsigned int seatID;
	unsigned int seatMarker;
	char lastName[nameLength];
	char firstName[nameLength];
}	seats[maxSeats];

int _tmain(int argc, _TCHAR* argv[])
{	int i;
	for(i=0;i<maxSeats;i++)	
		seats[i].seatID = (i+1);
	for(i=0;i<maxSeats;i++)
		seats[i].seatMarker = 0;
	char decision='a';
	
	while (decision!= 'e')
	{	decision = menuDisplay();
		switch(decision)
		{	case 'A' :
			case 'a' : printf("There are %d empty seats on this flight\n\n",emptySeats());
					break;
			case 'B' :
			case 'b' : listEmpty();
					break;
			case 'C' :
			case 'c' : assignSeat();
					break;
			case 'D' :
			case 'd' : deleteSeat();
					break;
			case 'E' :
			case 'e' : break;
			default : printf("Invalid Entry\n");
				break;
		}
		
		printf("\n");
	}
	
	return 0;
}

char menuDisplay (void)
{	char c;
	printf("Choose a function :\n");
	printf("   a)Show number of empty seats\n");
	printf("   b)Show list of empty seats\n");
	printf("   c)Assign a seat\n");
	printf("   d)Delete a seat assignment\n");
	printf("   e)Quit\n");
	scanf("%c",&c);
	return c;
}

int emptySeats (void)
{	int i;
	int count = 0;
	for(i=0;i<maxSeats;i++)
	{	if(seats[i].seatMarker == 0)
			count++;
	}
	return count;
}

void listEmpty (void)
{	int i;
	for(i=0;i<maxSeats;i++)
	{	if(seats[i].seatMarker == 0)
			printf("Seat number %d is unassigned\n",i+1);		
	}
	printf("\n");
}

void assignSeat (void)
{	int seat;
	printf("Select a seat to assign: ");
	scanf("%d", &seat);
	if(seats[seat-1].seatMarker != 1)
	{	printf("\nFill in information below to assign a passenger to seat number %d \n", seat);
		printf("Passenger first name: ");
		scanf("%s", &seats[seat-1].firstName);
		printf("Passenger last name: ");
		scanf("%s", &seats[seat-1].lastName);
		seats[seat-1].seatMarker = 1;
		printf("\nPassenger Information:");
		printf("\nSeat Number: %d\n", seat);
		printf("First Name: %s\n", seats[seat-1].firstName);
		printf("Last Name: %s\n", seats[seat-1].lastName);
		printf("SEAT CONFIRMED\n\n");
	}
	else
		printf("Seat %d is already taken", seat);
}

void deleteSeat (void)
{	int seat;
	char x[] = "";
	printf("Select a seat to delete: ");
	scanf("%d", &seat);
	if(seats[seat-1].seatMarker == 1)
	{	seats[seat-1].seatMarker = 0;
		strcpy(seats[seat-1].firstName, x);
		strcpy(seats[seat-1].lastName, x);
		printf("Seat %d has been deleted\n",seat);
	}
	else
		printf("Seat %d is not assigned\n",seat);
}

And here is what happens when I run:
-----------------------------------------------------------------------
Choose a function :
a)Show number of empty seats
b)Show list of empty seats
c)Assign a seat
d)Delete a seat assignment
e)Quit
a
There are 12 empty seats on this flight

Choose a function :
a)Show number of empty seats
b)Show list of empty seats
c)Assign a seat
d)Delete a seat assignment
e)Quit
Invalid Entry

Choose a function :
a)Show number of empty seats
b)Show list of empty seats
c)Assign a seat
d)Delete a seat assignment
e)Quit

-------------------------------------------------------------------------

It seems as if after it runs through the switch the first time my variable 'decision'
is getting assigned a different variable because it triggers the default switch
statement. I'm not sure what is going on so any help would be appreciated.

That's because a <enter> is two characters and scanf() is leaving the Enter key (newline) in the input buffer after you read out a single character.

Try it like this...

Code:

scanf(" %c",&c);

Note the space inserted between the " and % .... That tells scanf() to ignore invisible characters.

Thanks for the help it worked.