#include <stdlib.h>
#include <stdio.h>
#include <math.h>

#define max_num   100
#define SWAP(X, Y, TEMP)  ((TEMP = X), (X = Y), (Y = TEMP))

int main(int argc, char *argv[])
{
  int list[max_num];
  int i, j, num, min, temp;
  int mid, left = 0, right = 0, find_data, find_flag = -1;
  
  printf("Please input number:");
  scanf("%d", &num);
  if (num < 0 || num > max_num) {
    fprintf(stderr, "invalid data\n");
    exit(1);
  }
  for (i = 0; i < num; i++) {
    list[i] = rand() % 1000;
    printf("%d  ", list[i]);
  }
  printf("\n");

  for (i = 0; i < num; i++) {
    min = i;
    for (j = i + 1; j < num; j ++) {
      if (list[j] < list[min])
        min = j;
    }
    SWAP(list[i], list[min], temp);
  }
  
  printf("After select sort result:\n");
  for (i = 0; i < num; i ++)
    printf("%d  ", list[i]);  
  printf("\n");

  printf("Please input find data:");
  scanf("%d", &find_data);
  
  right = num - 1;
  while (left <= right) {
    mid = (left + right) / 2;
    if (list[mid] == find_data) {
      find_flag = mid;
      break;
    } else if (list[mid] < find_data) {
      left = mid + 1;
    } else 
      right = mid - 1;
  }
  if (find_flag != -1) {
    printf("Find data is sign: %d\n", find_flag);
  }
}

折半查找法_#define