this is a succsesful answer in C, but I want to understand it. Who can help me?

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

int main()
{
    int n, x=1, FM;
    int arr[1000];
    scanf("%d", &n);

   if(n<=1000 && n>=3)
   {
     for(int i=0; i<n; i++)
     {
         scanf("%d", &arr[i]);
     }

     FM=arr[0]+arr[1]+arr[2];

     for(int i=1; i<n-2; i++)
     {
         if(arr[i]+arr[i+1]+arr[i+2]>FM)
         {
             FM=arr[i]+arr[i+1]+arr[i+2];
             x=i+1;
         }
     }
   }
     printf("%d %d", FM, x+1);
     return 0;
}

Edited by author 10.10.2019 12:53