text: #ifndef headers
  #define headers
  
  #include<stdio.h>
  #include<stdlib.h>
  #include<unistd.h>
  #include<sys/types.h>
  #include<sys/wait.h>
  #include<string.h>
  
  #define STR_SIZE 100
  #define LIMIT 1000
  
  int mergeSort(int arr[], int begin, int end);
  int mergeBack(int begin, int mid, int end);
  int randomfill(int arr[], int len);
  void insertion_sort(int arr[], int len);
  
  #endif