#include <stdio.h>
int binsearch(int list[], int searchnum, int left, int right)
{
/*searchnum에 대해 list[0]<=list[1]<=...<=list[n-1]을 탐색.찾으면
그 위치를 반환하고 못찾으면 -1을 반환한다.*/
int mid;
mid=(left+right)/2;
if(right<=left){
return -1;
}else if(searchnum < list[mid]){
return binsearch(list,searchnum,left,mid-1);
}else if(searchnum>list[mid]){
return binsearch(list,searchnum,mid+1,right);
}else {
return mid;
}
}
/****** main program ******/
int main()
{
int data[16] = { 12,23,25,34,45,46,57,58,69,72,75,82,86,89,97,99 };
int found;
found = binsearch( data, 34, 0, 15 ); /* 34를 찾는다 */
if (found == -1) { printf(" Not Found n"); }
else { printf("* It's at %d !n", found); }
}
//원 소스
#include <stdio.h>
int binsearch(int list[], int searchnum, int left, int right)
{
/*searchnum에 대해 list[0]<=list[1]<=...<=list[n-1]을 탐색.찾으면
그 위치를 반환하고 못찾으면 -1을 반환한다.*/
int middle;
while(left <= right){
middle=(left+right)/2;
if( list[middle] < searchnum )
left = middle +1 ;
else if ( list[middle] > searchnum )
right = middle - 1;
else if ( list[middle] == searchnum )
return middle;
}
return -1;
}
/****** main program ******/
int main()
{
int data[16] = { 12,23,25,34,45,46,57,58,69,72,75,82,86,89,97,99 };
int found;
found = binsearch( data, 34, 0, 15 ); /* 34를 찾는다 */
if (found == -1) { printf(" Not Found n"); }
else { printf("* It's at %d !n", found); }
}