归并排序

#include <iostream>using namespace std;void Merge(int a[],int b[], int start, int mid, int end){int i=start,j=mid+1,k=start;while(i<=mid&&j<=end){if(a[i]>=a[j]){b[k]=a[j];k++;j++;}else{b[k]=a[i];i++;k++;}}while(i<=mid){b[k]=a[i];k++;i++;}while(j<=end){b[k]=a[j];j++;k++;}for(i=start;i<=end;i++) a[i]=b[i];}//内部使用递归void MergeSort(int a[],int b[], int start, int end){   if(start<end)   {   int mid=(start+end)/2;   MergeSort(a,b,start,mid);   MergeSort(a,b,mid+1,end);   Merge(a,b,start,mid,end);   }}int main(){    int a[8] = {50, 10, 20, 30, 70, 40, 80, 60};    int i, b[8];    for(i=0; i<8; i++)        cout<<a[i]<<" ";    cout<<endl;        MergeSort(a, b, 0, 7);    for(i=0; i<8; i++)        cout<<a[i]<<" ";    cout<<endl;    return 0;}