[C/C++ 演算法]- 二分搜尋法（搜尋原則的代表） – jashliao部落格

#include 
#include 
#include 
#define MAX 10
#define SWAP(x,y) {int t; t = x; x = y; y = t;}

void quickSort(int[], int, int);
int binarySearch(int[], int);
int main(void) {
srand(time(NULL));
int number[MAX] = {0};
int i;
for(i = 0; i < MAX; i++) {
number[i] = rand() % 100;
}
quickSort(number, 0, MAX-1);
printf("數列：");
for(i = 0; i < MAX; i++)
printf("%d ", number[i]);
int find;
printf("\n輸入尋找對象：");
scanf("%d", &find);
if((i = binarySearch(number, find)) >= 0)
printf("找到數字於索引 %d ", i);
else
printf("\n找不到指定數");
printf("\n");
return 0;
}
int binarySearch(int number[], int find) {
int low = 0;
int upper = MAX - 1;
while(low <= upper) {
int mid = (low+upper) / 2;
if(number[mid] < find)
low = mid+1;
else if(number[mid] > find)
upper = mid - 1;
else
return mid;
}
return -1;
}
void quickSort(int number[], int left, int right) {
if(left < right) {
int s = number[(left+right)/2];
int i = left - 1;
int j = right + 1;
while(1) {
while(number[++i] < s) ;  // 向右找
            while(number[--j] > s) ;  // 向左找
            if(i >= j)
break;
SWAP(number[i], number[j]);
}
quickSort(number, left, i-1);   // 對左邊進行遞迴
        quickSort(number, j+1, right);  // 對右邊進行遞迴
    }
}