折半查詢法——在有序整形陣列中尋找
阿新 • • 發佈:2018-11-14
#include<stdio.h>
#include<Windows.h>
int main()
{
int arr[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
int mid = 0;
int left = 0;
int right = sizeof arr / sizeof arr[0] - 1;
int key = 7;
while (left<=right)
{
mid = left + (right - left) / 2; //計算中間下標(防止溢位)
if (arr[mid] < key)
{
left = mid + 1;
}
else if (arr[mid]>key)
{
right = mid - 1;
}
else
{
printf("找到了:%d\n", mid);
break; //找到了返回下標
}
}
if (left > right)
printf("-1\n"); //找不到返回-1
system("pause");
return 0;
}
#include<Windows.h>
int main()
{
int arr[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
int mid = 0;
int left = 0;
int right = sizeof arr / sizeof arr[0] - 1;
int key = 7;
while (left<=right)
{
mid = left + (right - left) / 2; //計算中間下標(防止溢位)
if (arr[mid] < key)
{
left = mid + 1;
}
else if (arr[mid]>key)
{
right = mid - 1;
}
else
{
printf("找到了:%d\n", mid);
break; //找到了返回下標
}
}
if (left > right)
printf("-1\n"); //找不到返回-1
system("pause");
return 0;
}