My function doesn't do anything with arrays

Question

Function could replace first n elements from array A with last n elements of array B.

Output is

Array A

1 2 3 4 5

Array B

6 7 8 9 10

I tried to put printf (i) in every loop and it seems to be work fine but it do nothing with arrays a and b :(

void reparray(int *a, int *b, int n){
    int i;
    int last_element;
    int help[5] = {};

    i = 0;
    for (i; i<n; i++){
      help[i] = a[i];
    }

    last_element = 4;
    for (last_element; last_element>=n; last_element--){
        help[last_element] = b[last_element];
    }

    i = 0;
    for (i; i<n; i++){
        a[i] = help[i];
    }

    last_element = 4;
    for (last_element;last_element >= n; last_element--){
        b[last_element] = help[last_element];
    }


}


int main()
{
    int a[5] = {1, 2, 3, 4, 5};
    int b[5] = {6, 7, 8, 9, 10};
    int n,i;

    reparray(a, b, 2);

   printf("Array A\n");

    i = 0;
    for (i; i<5; i++){
       printf("%d\n", a[i]);
    }

    printf("Array B\n");

    i = 0;
    for (i; i<5; i++){
        printf("%d\n", b[i]);
    }

    return 0;
}

Answer 1

your 2 last loops in void reparray do nothing except copying exact things which were already in a and b

void reparray(int* a, int* b, int n) {
    int i;
    int last_element;
    int help[5] = {};

    i = 0;
    for (i; i < n; i++) {
        help[i] = a[i];
    }

    last_element = 4;
    for (last_element; last_element >= n; last_element--) {
        help[last_element] = b[last_element];
    }
    last_element = 4-1;
    i = 0;
    for (i = 0; i < n; i++) {
        a[i] = help[last_element];
        last_element++;
    }

    i = 0;
    for (i; i< n; i++) {
        b[i] = help[i];
    }


}

for other input change void reparray

void reparray(int* a, int* b, int n) {
    int i;
    int last_element;
    int help[5] = {};

    i = 0;
    for (i; i < n; i++) {
        help[i] = a[i];
    }

    last_element = 4;
    for (last_element; last_element >= n; last_element--) {
        help[last_element] = b[last_element];
    }
    last_element = 4 - 1;
    i = 0;
    for (i = 0; i < n; i++) {
        a[i] = help[last_element];
        last_element++;
    }
    last_element = 4;
    int first_element = 0;
    for (i = last_element - n + 1; i < last_element + 1; i++) {
        b[i] = help[first_element];
        first_element++;
    }


}