Issue with returning an array of type int from function

I have read through a lot of posts giving ways in which you can return an array of type int from a function. I have attempted to follow the approach of dynamically allocating the memory inside of the function using the malloc() function.

In the example code, I am using a function foo which calculates peaks in an array which are greater than a specified value.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* function declaration */
int *foo(int arr[],int size);
int main()
{
int test[] = {1,2,1,4,5,2,7,8,9,1}; //array of test data.
int *p;
p = foo(test,10);
int w;
for(w=0;w<5;w++)
    {
      printf(" Peak %d\t",p[w]); // This line is giving a non sensible answer.
    }
    free(p); // free the memory

return 0;
}

int *foo(int arr[],int size) {
    int j;
    int Peak_min = 3; // Minimum peak height
    int *ret = malloc(size * sizeof(*ret));
    if(!ret)  return 1;
    for (j = 0; j < size -1; ++j)
    {
        if ( (arr[j] < arr[j+1]) && (arr[j+1] > arr[j+2]) && (arr[j+1] > Peak_min))// Peak criteria
        {
            ret[j] = arr[j+1];
            printf(" Peak_No %d",ret[j]); // This line is giving the correct output.            
        }
    }
    return ret;
}

The output printed in the function gives 5 and 9, as expected. However, the output when I call the function in int main() gives non-sensible values. I am struggling to find the error with my code, any suggestions on how I can debug/fix this?

Update

I edited the for loop in the fucntion foo to

for (j = 0; j < size -2; ++j)
    {
        if ( (arr[j] < arr[j+1]) && (arr[j+1] > arr[j+2]) && (arr[j+1] > Peak_min))// Peak criteria
        {
            ret[j] = arr[j+1];
            printf(" Peak_No %d",ret[j]); // This line is giving the correct output.
        }
        else
        {
         ret[j] = 0;
        }
    }

I am now getting the output I wanted.