数组中的基本操作：顺序查找元素
#include <stdio.h>
#define SIZE 10
int main( )
{
int d[SIZE]={34, 43, 98, 72, 12, 47, 31, 43, 1, 78};
int i,key,index=-1;
printf("Input a key you want to search: ");
scanf("%d" , &key);
for(i=0; i<SIZE; i++)
if(key == d[i])
{
index = i;
break;
}
if(index >= 0)
printf("The index of the key is %d .\n", index);
else
printf("Not found.\n");
return 0;
}
用二分方法查找有序数组：一次比较, 缩减一半的规模
#include <stdio.h>
#define SIZE 10
int main( )
{
int d[SIZE] = {1, 3, 9, 12, 32, 41, 45, 62, 75, 77};
int low, high,mid,key,index=-1;
printf("Input a key you want to search: ");
scanf("%d" , &key);
low=0,high=SIZE-1;
while(low<=high)
{
mid=(low+high)/2;
if(d[mid]==key){
index=mid; break;
}
else if(d[mid]>key)
high=mid-1;
else
low=mid+1;
}
if(index >= 0)
printf("The index of the key is %d .\n", index);
else
printf("Not found.\n");
return 0;
}
