这个求最大子序列的程序为什么不能输出正确答案？该怎么解决

#include <stdio.h>
#include <conio.h>
#define N 6

main()
{
    int i;
    int a[N]={-2,11,-4,13,-5,-2};
    printf("the old older is:n");
        for(i=0;i<N;i++)
            printf("%d  ",a[i]);
                printf("n");
                     i=MaxSubsequenceSum4(a,N);
                 printf("the max is %dn",i);
                printf("n");
        getch();
}

int
MaxSubsequenceSum4(const int a[],int n)     
{
    int ThisSum,MaxSum,j;

     ThisSum=MaxSum=0;
      for(j=0;j<n;j++)
      {
        ThisSum+=a[j];

         if(ThisSum>MaxSum)
            MaxSum=ThisSum;
         else if(ThisSum<0)
            MaxSum=0;
      }
     return MaxSum;
}