找出数组中第二大数

#include "stdio.h"
#include "stdlib.h"

#define LEN(arr) sizeof(arr)/sizeof((arr)[0])

struct Result{
int Max;
int SecondMax;
};

void GetSecondMax(int* arr, int len, Result* rlt)
{
for(int i=0; i< len-1; i=i+2)
{
if(NULL==arr[i+1])
{
if(arr[i]>rlt->Max)
rlt->Max=arr[i];
else if(arr[i]>rlt->SecondMax)
rlt->SecondMax=arr[i];
}
if(arr[i]>arr[i+1])
{
if(arr[i]>rlt->Max)
rlt->Max=arr[i];
if(arr[i+1]>rlt->SecondMax)
rlt->SecondMax=arr[i+1];
}
if(arr[i]<arr[i+1])
{
if(arr[i+1]>rlt->Max)
rlt->Max=arr[i+1];
if(arr[i]>rlt->SecondMax)
rlt->SecondMax=arr[i];
}
}
}

int main()
{
int test[10]={3,2,4,1,5,2,7,9,0};
Result* rlt = (Result*)malloc(sizeof(Result));
int len=LEN(test);
GetSecondMax(test, len, rlt);
printf("Max=%d\nMin=%d\n", rlt->Max, rlt->SecondMax);
getchar();
}