#include 
     
      using namespace std;#define MAX 100void merge(int arr1[],int len1,int arr2[],int len2,int arr3[],int len3) {    len3--;     len1--;     len2--;     while(len1 >= 0 && len2 >= 0)     {        if (arr1[len1] >= arr2[len2])        {           arr3[len3--] = arr1[len1--];        }        else        {           arr3[len3--] = arr2[len2--];        }     }     while (len1 >= 0)     {        arr3[len3--] = arr1[len1--];     }    while (len2 >= 0)     {        arr3[len3--] = arr2[len2--];     } }void main(){       int arr1[] = {
    1,2,4,5,6};    int arr2[] = {
    2,3,4,9};    int len1 = sizeof(arr1)/sizeof(int);    int len2 = sizeof(arr2)/sizeof(int);    int len3 = len1 +len2;    int arr3[MAX];    cout<<"合并前:"<