Can someone explain how to append an element to an array in C programming?
You can have a counter (freePosition), which will track the next free place in an array of size n.
int arr[10] = {0, 5, 3, 64};
arr[4] = 5;
EDIT: So I was asked to explain what's happening when you do:
int arr[10] = {0, 5, 3, 64};
you create an array with 10 elements and you allocate values for the first 4 elements of the array.
Also keep in mind that arr
starts at index arr[0]
and ends at index arr[9]
- 10 elements
arr[0] has value 0;
arr[1] has value 5;
arr[2] has value 3;
arr[3] has value 64;
after that the array contains garbage values / zeroes because you didn't allocated any other values
But you could still allocate 6 more values so when you do
arr[4] = 5;
you allocate the value 5 to the fifth element of the array.
You could do this until you allocate values for the last index of the arr
that is arr[9]
;
Sorry if my explanation is choppy, but I have never been good at explaining things.
There are only two ways to put a value into an array, and one is just syntactic sugar for the other:
a[i] = v;
*(a+i) = v;
Thus, to put something as the element at index 4, you don't have any choice but arr[4] = 5
.
For some people which might still see this question, there is another way on how to append another array element(s) in C. You can refer to this blog which shows a C code on how to append another element in your array
.
But you can also use memcpy()
function, to append element(s) of another array. You can use memcpy()
like this:
#include <stdio.h>
#include <string.h>
int main(void)
{
int first_array[10] = {45, 2, 48, 3, 6};
int scnd_array[] = {8, 14, 69, 23, 5};
int i;
// 5 is the number of the elements which are going to be appended
memcpy(first_array + 5, scnd_array, 5 * sizeof(int));
// loop through and print all the array
for (i = 0; i < 10; i++) {
printf("%d\n", a[i]);
}
}