struct subsequence{
 int value;
 int start;
 int end;
};
subsequence maxsubsequence(int a[],int N)
{
subsequence maxsub;
maxsub.value=0;maxsub.start=0;maxsub.end=0;
int sum=0;
for(int i=0;i<N;i++)
 {
 sum+=a[i];
 if(sum>maxsub.value)
  {maxsub.value=sum;
   maxsub.end=i;
  }
  else if(sum<0)
  {
  sum=0;
  if(maxsub.value==0)maxsub.start=i+1;
  }
 }
return maxsub;
}
这里是不是出错了if(maxsub.value==0)maxsub.start=i+1;
如果a[]={3,-5,4,9}呢？
麻烦高手帮忙一下

这是伪码，我想问的是不是有逻辑错误if(maxsub.value==0)maxsub.start=i+1;这是不是错了，如果a[]={4,-5,5,6}maxsub.start的直会对吗，如果对的话麻烦解释一下if(maxsub.value==0)maxsub.start=i+1;的逻辑作用（不是这句代码的意思）；