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stack of queues

I have a homework assignment in C. I am suppose to have a train station that has trains(stacks) and cars(queues) in it. When they are to depart I am suppose to print out that they have departed also I should add a car remove a car and print that out as well. I am lost with wirting the function that does this.
Here is the code that I have up to this point if anyone can help that would be great.

if this is removed the program runs.
int remove_car(struct train* q)
{
      if (
            isQueueEmpty(s)
            printf("there is only one car on the train.");
}
any ideas would be great

/*George Regas
  COP 3502
  g0616085
  Oct 22, 2008
  Assignment 3:
  Bob's Train Station
*/
#include <stdio.h>
 
struct station* new_station(int initial_Size);
struct train* new_train(int initial_size);	
void print_stack(struct station* s);
void print_queue(struct train* q);
void add_train(struct station* s, struct train* q, int num_cars, FILE* fname);
int remove(struct station* s, struct train* q);
int last_car(struct queue* q);
 
struct train
{
    int* store;
    int front;
    int back;
    int size;
};
 
struct station
{
    struct train * store;
    int top;
    int size;
};
 
struct station* new_station(int initial_Size) //my stack
{
    struct station* s;
    
    s = malloc(sizeof(struct station));
    
    s->store = calloc(initial_Size, sizeof(struct train));
    s->top = 0;
    s->size = initial_Size;
    
    return s;
}
 
void add_train(struct station* s, struct train* q, int num_cars, FILE* fname)//function for reading the train with the cars
{
    int i;
    int j;
    int car;
 
printf("Train Departed: ");
 
    for(i = 0; i < num_cars; i++)
    {
        fscanf(fname, "%d", &car);
		printf("%d ", car);
        q->store[q->back] = car;
        q->back = (q->back + 1) % q->size;
        //expand queue check
    }
printf("\n");
 
    s->store[s->top] = (*q);
    s->top++;
    for(j = 0; j < s->top; j++)
    {
//		printf("%d\n", s->store[j]);
    }
    return;   
}
 
struct train* new_train(int initial_size) //my queue
{
    struct train* q;
    
    q = malloc(sizeof(struct train));
    q->store = calloc(initial_size, sizeof(int));
    q->front = 0;
    q->back = 0;
    q->size = initial_size;
    
    return q;   
}
 
void print_queue(struct train* q)
{
	int i;
	
	for(i=q->front; i < q->back; i++)
		printf("%d", q->store[i]);
 
}
void print_stack(struct station* s)
{
    int i; // index used in for loop
    
    // loop through stack from top to bottom, printing them out as we go
    for(i = 0; i < s->top; i++)
        print_queue;
       
}
// This function returns true if the queue is empty and false otherwise
int isQueueEmpty(struct train* q)
{
    // if the front and back are equal to each other then the queue is empty
    return q->front == q->back;   
}
int dequeue(struct train* q)
{
    int rval = q->store[q->front];  // value of the integer at the front of the queue
 
    // Move front up one position in the store array
    // The % (modulus) operator is used to ensure that front does not exceed the size
    //   of the array.
    // Keep in mind that we could loop around in the store array if front > back.
    q->front = (q->front + 1) % q->size;
    
    // return the value that just got dequeued
    return rval;
}
int remove_car(struct train* q)
{
	if (
		isQueueEmpty(s)
		printf("there is only one car on the train.");
}
int main(void)
{
	FILE *fp;
    char fname[32];	
	int i, n;
	char action[20];
	struct station* s;
	struct train* q;
	int num_cars;
 
	printf("Welcome to Bob's Train Station\n");
	printf("What is the name of the input file?\n");
	scanf("%s", fname);
 
	fp = fopen(fname, "r");
	if (fp == NULL)
		printf("ERROR");
	
	printf("Here is the output!:\n");
	
	fscanf(fp, "%d", &n);
	s=new_station(10);
	for(i=0; i<n; i++)
	{
		fscanf(fp,"%s", action);
		if(strcmp(action,"new_train")==0)
		{
			fscanf(fp, "%d", &num_cars);
			q=new_train(num_cars);				
			add_train(s, q, num_cars, fp);
		}
/*		else if(strcmp(action, "remove_car")==0);
		{
			place funtion here
		}
		else if(strcmp(action, "add_car")==0);
		{
			place funtion here
		}
		else if(strcmp(action, "train_departs")==0);
		{
			place funtion here
		}//*/
	}
	fclose(fp);
		
	system("PAUSE");
	return 0;
}

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sunnycoder

Cars are in a queue and you need functions to add/delete from queue

Addition()
{
check if addition would lead to overflow - i.e. you should not be trying to insert more elements than the queue can handle. If that is the case, return error

add an element to the end of the queue

return success
}

Deletion()
{
check for underflow ... i.e. are you trying to delete from empty queue. if yes then return error

remove element from head of the queue

return success
}

struct train
{
int* store;
int front;
int back;
int size;
};

Your queue would be a dynamically allocated array ... so you would need a circular queue kind of implementation in order to reuse the array locations. Whenever your front or back reach max value, you need to reset them to 0. one way of doing that is %capacity every time you increment them