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12/05/2008 at 06:53AM PST, ID: 23960378

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8.2

A heap function

Asked by mikeregas in C Programming Language

I have a program that is due tonight and I am stuck. Can someone take a look at this code and tell me, where I am lost. I have set that all the data from the file that is read is stored in an array and I have a struct for that array. I just cannot seem to figure out how to get it to work. I have one error and I am lost. I will attach the code, assignment and sample.txt file for you to look at.

In short the program is suppose to read the file look at the first string and decide if it needs to be added to the heap or taken off the heap, the second is an interger(priority) and the last is a string that is the "program."

Thanks

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             #include <stdio.h>
#include <stdlib.h>
 
struct tasks
{
	int priority;
	char command[24];
};
struct heap
{
    struct tasks* store;
    int size; // Number of values in the heap
    int capacity; // Maximum number of values before we
                  // expand the heap
};
 
struct heap* heapify(int array[], int num_elements);
 
struct heap *new_heap(int initial_capacity);
void percolate_down(struct heap* h, int position);
void percolate_up(struct heap* h, int position);
void expand_heap(struct heap* h);
void deletemax(struct heap* h);
void insert(struct heap* h, int value);
 
struct heap *new_heap(int initial_capacity)//new data is stored
{
    struct heap *h;
    
    h = malloc(sizeof(struct heap));
    h->store = calloc(initial_capacity, sizeof(struct tasks));
    h->size = 0;
    h->capacity = initial_capacity;
    
    return h;
}
 
 
void percolate_down(struct heap* h, int position)
{
    int temp;
    if(position * 2 > h->size)
        return;
        
    if(position * 2 == h->size)
    {
		if(h->store[position*2].priority <= h->store[position].priority)
            return;
        else
        {
            temp = h->store[position].priority;   
            h->store[position].priority = h->store[position*2].priority;
            h->store[position*2].priority = temp;
            return;
        }
    }
    
    if(h->store[position*2].priority <= h->store[position].priority 
            && h->store[position*2 + 1].priority <= h->store[position].priority)
        return;
    
    // Percolate to the left
    if(h->store[position*2].priority >= h->store[position*2 + 1].priority)
    {
        temp = h->store[position].priority;
        h->store[position].priority = h->store[position*2].priority;
        h->store[position*2].priority = temp;
        percolate_down(h, position * 2);
        return;
    }
    
    // Percolate to the right
    temp = h->store[position].priority;
    h->store[position].priority = h->store[position*2 + 1].priority;
    h->store[position*2 + 1].priority = temp;
    percolate_down(h, position * 2 + 1);
 
}
 
void percolate_up(struct heap* h, int position)
{
    int temp;
    
    if(position == 1)
        return;
    if(h->store[position/2].priority >= h->store[position].priority)
        return; 
    
    temp = h->store[position].priority;
    h->store[position].priority = h->store[position/2].priority;
    h->store[position/2].priority = temp;
    
    percolate_up(h, position/2);
}
 
void expand_heap(struct heap* h)
{
    struct tasks* newstore;
    int i;
    
    newstore = calloc(h->capacity * 2, sizeof(struct tasks));
    
    for(i = 1; i <= h->size; i++)
    {
		newstore[i] = h->store[i].priority;   
    }
    free(h->store);
    h->store = newstore;
    h->capacity *= 2;
}
 
struct heap* heapify(int array[], int num_elements)// sorts data
{
    struct heap* h;
    int i;
    
    h = new_heap((num_elements + 1) * 2);
    
    for(i = 0; i < num_elements; i++)
    {
        h->store[i+1].priority = array[i];   
    }
    h->size = num_elements;
    
    for(i = h->size / 2; i >= 1; i--)
        percolate_down(h, i);
        
    return h;
}
 
void deletemax(struct heap* h)
{
	printf("Program %s with priority %d has been executed.\n", h->store[1].command, h->store[1].priority);
 
	strcpy(h->store[1].command, h->store[h->size].command);
	h->store[1].priority = h->store[h->size].priority;
    h->size--;
    
    percolate_down(h, 1);
}
 
void insert(struct heap* h, int value)
{
	printf("Program %s with priority %d has arrived.\n", h->store->command, h->store->priority);
 
	h->size++;
    if(h->size >= h->capacity)
        expand_heap(h);
    
	h->store[h->size].priority = value;
    percolate_up(h, h->size);
}
 
int main(void)
{
	FILE *ifp;
	char infile[48];
	char command[24];
	int valid = 0, priority;
	int i, n;
	char action;
	struct tasks p;
	struct heap *h;
	(h)=new_heap(48);
 
	
	while(!valid)
	{
		printf("What is the name of the input file?\n");
		scanf("%s", infile);
		ifp = fopen(infile, "r");
 
		if(ifp == NULL)
			printf("File not found!\n");
		else
		{
			valid = 1;
			
			for(i = 0; i < n; i++)
			{
				fscanf(ifp, "%s", action);
				if(strcmp(action, "new")==0)
				{
					fscanf(ifp, "%d %s", p.priority, p.command);
					printf("Program %s with priority %d has arrived.\n", p.command, p.priority);
 
				}
				else if(strcmp(action, "execute")==0)
				{
					if (h->size==0)
						printf("Heap is empty, no programs executed!\n");
					else 
					{
						deletemax(&h);
					}
				}
				
			}
		
		}
	}
	valid = 0;
 
	system("PAUSE");
	return 0;
}

           
         

Attachments:

sample.txt (139 bytes) (File Type Details)

sample text file I am using

Assignment5.doc (28 KB) (File Type Details)

assignment discription.

20090824-EE-VQP-74 - Hierarchy / EE_QW_2_20070628

1. Infinity08561,040
2. evilrix204,131
3. mrjoltcola187,564
4. jkr149,687
5. ozo134,525
6. itsmeandn...92,796
7. masheik68,342
8. pgnatyuk57,959
9. Kdo57,090
10. sunnycoder56,749
11. fridom50,492
12. Let_Me_Be49,246
13. DanRollins27,537
14. _phoenix_19,551
15. woolmilkp...18,264
16. jaime_oliv...17,134
17. lhl6016,254
18. trinitrotolu...15,372
19. abel15,296
20. Zoppo13,150
21. ikework12,814
22. ewest0212,750
23. duncan_roe12,564
24. Subrat2...12,163
25. flob912,150

1. Infinity081,715,300
2. sunnycoder1,090,983
3. jkr926,308
4. Kdo882,217
5. ozo600,952
6. evilrix415,261
7. grg99299,856
8. PaulCasw...299,635
9. itsmeandn...281,273
10. jaime_oliv...230,946
11. fridom225,588
12. mrjoltcola187,564
13. brettmjohn...182,528
14. ankuratvb157,866
15. imladris147,553
16. cwwkie129,383
17. Axter100,363
18. akshayxx96,671
19. josgood83,881
20. AlexViroc...70,328
21. gj6270,227
22. rbr69,997
23. masheik68,342
24. cup63,653
25. ssnkumar61,996

A heap function

Asked by mikeregas in C Programming Language

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