I'm new in c. I want to create array, and after it delete it, and then put another array into it. How can I do it?
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1Can you tell us how you allocated the array? If you used malloc, you can use free to deallocate it, then allocate a new one.Rafe Kettler– Rafe Kettler2011-05-05 14:52:53 +00:00Commented May 5, 2011 at 14:52
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1If you use malloc, you have code. If you have code, you should post it.abelenky– abelenky2011-05-05 15:17:55 +00:00Commented May 5, 2011 at 15:17
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2 Answers
If you are looking for a dynamic array in C they are fairly simple.
1) Declare a pointer to track the memory,
2) Allocate the memory,
3) Use the memory,
4) Free the memory.
int *ary; //declare the array pointer
int size = 20; //lets make it a size of 20 (20 slots)
//allocate the memory for the array
ary = (int*)calloc(size, sizeof(int));
//use the array
ary[0] = 5;
ary[1] = 10;
//...etc..
ary[19] = 500;
//free the memory associated with the dynamic array
free(ary);
//and you can re allocate some more memory and do it again
//maybe this time double the size?
ary = (int*)calloc(size * 2, sizeof(int));
Information on calloc() can be found here, the same thing can be accomplished with malloc() by instead using malloc(size * sizeof(int));
Comments
It sounds like you're asking whether you can re-use a pointer variable to point to different heap-allocated regions at different times. Yes you can:
void *p; /* only using void* for illustration */
p = malloc(...); /* allocate first array */
... /* use the array here */
free(p); /* free the first array */
p = malloc(...); /* allocate the second array */
... /* use the second array here */
free(p); /* free the second array */
