Program to run function - c

Question

I have a question for my assignment:
Write a function called second which takes, as parameters, an array of
positive integers and also an integer representing the size of the
array. The function returns the value of the second largest integer in
the array. If the largest integer in the array repeats, then the
second largest integer is also the largest. For example, if we have
{1, 2, 3, 4, 5, 5 }, the second largest integer is
5. The function should not change the contents of the array in any way. You can assume that the size of the array is at least two.
What I've done:
int second(const int arr[], int size)
{
int num1,num2;
int i;
if(arr[0]>arr[1])
{
num1=arr[0];num2=arr[1];
}
else
{
num1=arr[1];num2=arr[0];
}
for (i=2; i<size; i++)
{
if (arr[i]>num1)
{
num2=num1;
num1=arr[i];
}
else if (arr[i] > num2)
{
num2=arr[i];
}
}
return num2;
}
I have no idea how to type a program that can run the above function and display the integer '5'

Answer 1

The function should not change the contents of the array in any way.
Use a temporary array to perform all the operations. Simply copy the elements from the old array to the new temp array.
Write a function called second which takes, as parameters, an array of
positive integers and also an integer representing the size of the
array
Case 1: if the array is unsorted
You could just sort the elements(ascending order) and return the second last element.
Case 2: If the array is sorted
Just return the second last element.
There are lots of sorting algorithms like quicksort and mergesort which give you a better runtime but you could use bubble sort as well if there is no constraint on time complexity.
Additional Hint:
int second(const int arr[], int size)
{
int temp[size]; //<-----use a temporary array as you're not allowed to modify the original array
int i;
for(i=0;i<size;i++)
{
//copy the elements
}
//sort the temp array in ascending order
return temp[size-2]; //<----return the second last elements
}

Answer 2

I am not looking at your function second. I will leave that to you as an exercise.
To run this function, you will need to make a main program which will create this array and call this function.
#include <stdio.h>
int second(const int arr[], int size);
int main(void)
{
int arr[] = {1,2,3,4,6,7};
int N = sizeof(arr)/sizeof(arr[0]);
printf ("%d ", second(arr, N));
}
You can add your code below the code here and compile.