about arrays in c++ and shifting the elements - c++

Question

I was practicing my c++ skills and I went into a question.
I have an array of 20 elements, 10 of them were declared before EX: list[1,2,3,4,5,6,7,8,9,10].
My job was to write a function that inserts the last elements
but after each element of the existing ones for EX: list[1, 0, 2, 8, 3, 9, 4, 10, 5 ...] etc.
what I did is declaring the last 10 elements to 0
void insertNum(int list[], int &count){
srand(time(NULL));
count = 20;
int temp = 0;
int i, j, min;
for (int i = 10; i < count; i++) {
list[i] = 0;
}
}
but I couldn't find the complete solution and it's killing me.
any ideas about how to do it?
this the whole code
#include <iostream>
#include <ctime>
using namespace std;
const int CAP = 20;
void buildList(int[], int &count);
void printList(int[], int count);
void insertNum(int list[], int &count);
int main(){
int list[CAP], count = 0;
buildList(list, count);
cout << "Original List!" << endl;
printList(list, count);
insertNum(list, count);
cout << "List after inserts!" << endl;
printList(list, count);
return 0;
}
void buildList(int list[], int &count){
srand(time(NULL));
count = 10;
for (int i = 0; i < count; i++)
{
list[i] = rand() % 100;
}
}
void printList(int list[], int count){
for (int i = 0; i < count; i++)
{
cout << list[i] << endl;
}
}
void insertNum(int list[], int &count){
}

Answer 1

I didn't understand the question fully, But if I am right you want to create a function that inserts one element after each element of an existing array. This might be what you are looking for. If not please rephrase the problem.
srand(time(NULL)); // need to do in main function only.
int oldArray[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
int finalArray[20] = { 0 };
for (int i = 0; i < 20; i++)
{
int newElement = rand()%11+10; //random number between 10 to 20. Figure out what and from where new element will come from
if (i % 2 == 0)
finalArray[i] = oldArray[i / 2];
else
finalArray[i] = newElement;
}