c++ - Merge sort not working completely -

the code have made merge sort given below. thing on giving input output 3 2 1 5 0. going wrong?

#include <iostream> #include <cmath> using namespace std;  int d[100];  void merge(int a[], int b[], int c[], int n) { int n2=floor(n/2); int i=0, j=0, k=0; while(i<n2 && j<(n-n2)) {     if(b[i]<c[j])     {         d[k++]=b[i++];     }     else if(b[i]>c[j])     {         d[k++]=c[j++];     } }     if(i==n2)     {         if(j<(n-n2))         {             d[k++]=c[j++];         }     }     if(i<n2)     {         d[k++]=b[i++];     } }   void mergesort(int a[], int n) { int n2=floor(n/2); int b[50],c[50]; int i,j=0,k=0; for(i=0;i<n2;i++) {     b[i]=a[k++]; } while(k<n) {     c[j++]=a[k++]; } merge(a,b,c,n); }  int main() { int a[]={5,4,3,2,1}; int n=5; mergesort(a,n); for(int i=0;i<n;i++) {     cout<<d[i]<<endl; } } 

the main problem arrays (b , c) passed merge not sorted. other problems algorithm not recursive , merge not put numbers b , c a.

a version seems work minimal changes code be

void merge(int a[], int b[], int c[], int n) {   int n2=floor(n/2);   int i=0, j=0, k=0;   while(k<n)   {     if((j == (n-n2) || b[i]<c[j]) && < n2)     {       a[k++]=b[i++];     }     else     {       a[k++]=c[j++];     }   } }   void mergesort(int a[], int n) {   int n2=floor(n/2);   int b[50],c[50];   int i,j=0,k=0;   for(i=0;i<n2;i++)   {     b[i]=a[k++];   }   while(k<n)   {     c[j++]=a[k++];   }   if(n2 > 1) {     mergesort(b, n2);   }   if(n - n2 > 1) {     mergesort(c, n - n2);   }   merge(a,b,c,n); }  int main() {   int a[]={5,4,3,2,1};   int n=5;   mergesort(a,n);   for(int i=0;i<n;i++)   {     cout<<a[i]<<endl;   } }