两个练习题

冒泡排序和二分查找的练习。

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#include <stdio.h> #include <assert.h> #include <stdlib.h> /* srand rand */ #include <time.h> #include <unistd.h>   static int binary(int arr[], const int size, const int n) { int high, low, mid;   assert(arr != NULL); assert(size > 0);   high = size - 1; low = 0;   while (low <= high) { mid = (high + low) / 2;   if (arr[mid] == n) { return mid; } else if (arr[mid] > n) { high = mid - 1; } else if (arr[mid] < n) { low = mid + 1; } }   return -1; }   static void maopao(int arr[], const int n) { int i, j, temp;   assert(arr != NULL); assert(n > 0);   for (i = 0; i < n; i++) { for (j = n - 1; j > i; j--) { if (arr[j] < arr[j-1]) { temp = arr[j]; arr[j] = arr[j-1]; arr[j-1] = temp; } } } }   static void print(const int arr[], const int n) { int i;   for (i = 0; i < n; i++) { printf("%d,", arr[i]); }   printf("\n"); }   int main(void) { int arr[20]; int i; int b_ret, len;   srand(time(NULL)); for (i = 0; i < 20; i++) { arr[i] = rand() % 100; }   len = sizeof(arr)/sizeof(int);     print(arr, len); maopao(arr, len); print(arr, len);   b_ret = binary(arr, len, 47);   if (b_ret != -1) { printf("47 is in %d\n", b_ret); } else { printf("don not exist!\n"); }   return 0; }