runtime error

[zebani]

Hi everyone, working on a data structers project on dev-c++ as compiler and problem is when compile&run it freezes but when click debug, (magically) it works. So what do you think I missing

[grumpy]

Your code is probably doing an invalid operation with a pointer. Anything that reorganises how your program uses memory can affect what happens as a result of an invalid pointer operation (including symptoms seeming to disappear when debugging, but coming back otherwise).

[zebani]

my struct is like that:

struct charDesc
{
      char ch;
      int freq;
      int index;
};
struct charDesc chars[256];


struct HeapStruct
{
      int capacity;
      int size;
      struct charDesc *elements;
};
typedef struct HeapStruct *priorityQueue;

So can't see the Error in this function.

void InsertPriorityQueue(int index,int freq,char ch, PriorityQueue h) {
    int i;


    if (IsFullPriorityQueue(h)) 
    {
        printf("Priority queue is full!\n");
        return;
    }
    h->size++;
    for (i = h->size; h->elements[i/2].freq > freq; i /= 2)
        {
             h->elements[i].ch = h->elements[i/2].ch;
             h->elements[i].freq = h->elements[i/2].freq;
             h->elements[i].index = h->elements[i/2].index;
        }
    h->elements[i].index = index;
    h->elements[i].freq = freq;
    h->elements[i].ch = ch;
}

[zebani]

any opinion?

[oogabooga]

You are starting your for loop at i = h->size, which may be out of range (depending on the rest of your code). You may want i = h->size - 1 instead.

[iMalc]

Don't know about your runtime error as there isn't enough info to find that, but I'd certainly change this:

             h->elements[i].ch = h->elements[i/2].ch;
             h->elements[i].freq = h->elements[i/2].freq;
             h->elements[i].index = h->elements[i/2].index;

to just this:

             h->elements[i] = h->elements[i/2];

Entire structures can be copied with a single assignment statement.

[zebani]

Thank you for all guys. The thing is code working now without changes. I guess dynamically allocated memory caused this crash so when debugging there was no error. And thanks for hint iMalc, I wasn't sure this way is OK