當sizeof 運算元為 pointer 時結果的小不同

int main()
{
 int kids[ ]={1,2,3,4,5};
 int *ptr=kids;
 printf("*ptr=%d\n",*ptr);
 printf("sizeof kids=%d\n",sizeof(kids));
 printf("sizeof ptr=%d\n",sizeof(ptr));
 return 0;
}

//though kids->1, sizeof(kids)=sizeof(int)*5
//let ptr=kids