4.数组-用指针来控制数组

#include <stdio.h>
void getsum(int pt[],int size );
void getsum1(int * head,int * tail );

int main()
{
    int i_arr[5] = { 1, 20, 3, 4, 5 };
    int *pt;
    getsum(i_arr,5);
    getsum1(i_arr,&i_arr[4]);
    printf("获取指定位置的元素值:索引方式-%d ,指针方式-%d\n", i_arr[4] ,*(i_arr + 4 ) );
    printf("one-%d two-%d\n", *i_arr+1, 0 );
    
    printf("%zd\n", &i_arr[2] - i_arr );


    return 0;
}
//参数为:数组头指针、数组长度
void getsum(int pt[],int size )
{
  int sum = 0;  
  for (int i = 0; i < size; ++i)
  {
     sum = sum + *(pt);
     pt++;
  }
  printf("%d\n", sum);
  
  return ;
}
//参数为:数组头指针、数组尾指针
void getsum1(int * head,int * tail )
{
  int sum = 0;
  while( head <= tail )
  {
    sum = sum + *head;
    head++;
  }  
  printf("%d\n", sum);

  return;
}