A heap function

#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;
}

                                  

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61:
62:
63:
64:
65:
66:
67:
68:
69:
70:
71:
72:
73:
74:
75:
76:
77:
78:
79:
80:
81:
82:
83:
84:
85:
86:
87:
88:
89:
90:
91:
92:
93:
94:
95:
96:
97:
98:
99:
100:
101:
102:
103:
104:
105:
106:
107:
108:
109:
110:
111:
112:
113:
114:
115:
116:
117:
118:
119:
120:
121:
122:
123:
124:
125:
126:
127:
128:
129:
130:
131:
132:
133:
134:
135:
136:
137:
138:
139:
140:
141:
142:
143:
144:
145:
146:
147:
148:
149:
150:
151:
152:
153:
154:
155:
156:
157:
158:
159:
160:
161:
162:
163:
164:
165:
166:
167:
168:
169:
170:
171:
172:
173:
174:
175:
176:
177:
178:
179:
180:
181:
182:
183:
184:
185:
186:
187:
188:
189:
190:
191:
192:
193:
194:
195:
196:
197:
198:
199:
200:
201:
202:
203:
204:
205:
206: