c++ - Merge sort make wrong answer -

i trying implement merge-sort, code:

#include <stdio.h> #include <stdlib.h> #include <iostream> #include <fstream> using namespace std; void merge_inplace (int *elem , int *axu, int lo, int mid, int hi) {     int =lo;     int j= mid +1;     (int k=lo;k<hi; k++)     {         axu[k]=elem[k];     }     for(int k=lo; k<hi;k++)     {         if(i> mid)             elem[k]=axu[i++];         else if(j> hi)             elem[k]=axu[j++];         else if (axu[i]<axu[j])             elem[k]= axu[i++];         else elem[k]= axu[j++];     } }  void mergesort(int *elem ,int *axu, int lo,int hi) {     if(hi<=lo) return;     int mid = lo + (hi-lo)/2;     mergesort(elem,axu, lo, mid);     mergesort(elem,axu, mid+1,hi);     merge_inplace(elem,axu,lo, mid, hi ); }  int main() {     ifstream in_file ;     ofstream out_file;     int size =0;     int element;     int* elem;     in_file.open("in_file.txt");     if (!in_file )perror ("error openning file");       in_file >> size;     elem = new int[size];      (int i=0; i<size;i++)     {         in_file >> elem[i];     }      int * axu = new int [size];     mergesort (elem,axu,0,size-1);      out_file.open("out_file.txt");      if (out_file.fail())     {         printf( "error opening file output.\n");          return 0;     }     (int i=0; < size; i++)     {         out_file << elem[i];     }     out_file.close();     return 0; } 

the out put of program in "out_file.txt "is :

-842150451-842150451-842150451-842150451-842150451-842150451-33686019-1414812757-84215045110

after debugging found when merge function returns element array destroy , make values wrong

my input file contain (one integer per line ):

10 9 7 5 1 8 3 6 4 2 10

some mistake on merge-sort & transferring aux initialization merge sort function

#include <stdio.h> #include <stdlib.h> #include <iostream> #include <fstream> using namespace std; void merge_inplace (int *elem , int *axu, int lo, int mid, int hi) {      int =lo;     int j= mid +1;     (int k=0;k<=hi; k++)  // <------------- transfer initialization merge      {         axu[k]=elem[k];     }     for(int k=lo; k<=hi;k++)     {         if(i> mid)             elem[k]=axu[j++];   // <----------------- i<--->j         else if(j> hi)             elem[k]=axu[i++];   // <------------------ i<--->j         else if (axu[i]<axu[j])             elem[k]= axu[i++];         else elem[k]= axu[j++];     } } void mergesort_book(int *elem ,int *axu, int lo,int hi) {     if(hi<=lo) return;     int mid = lo + (hi-lo)/2;     mergesort_book(elem,axu, lo, mid);     mergesort_book(elem,axu, mid+1,hi);     merge_inplace(elem,axu,lo, mid, hi ); } //static void merge(vector <int> elements, ) int main() {         ifstream in_file ;         ofstream out_file;         int size =0;         int element;         int* elem;         in_file.open("in_file.txt");         if (!in_file )perror ("error openning file");                       in_file >> size;                     elem = new int[size];          (int i=0; i<size;i++)         {             in_file >> elem[i];         }          int * axu = new int [size];          mergesort_book (elem,axu,0,size-1);          out_file.open("out_file.txt");             if (out_file.fail())             {       printf( "error opening file output.\n");        return 0;    }         (int i=0 ; < size; i++)         {             //out_file << elem[i];              printf("%d\n", elem[i]);         }         out_file.close(); return 0; }