#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<windows.h>

int main()
{
  char arr1[] = "白子寰是一位学习C语言的帅哥!!!";
  char arr2[] = "##############################";
    //两个双引号里的内容字符要对应
 
  int left = 0;
  int right = strlen(arr1) - 1;
  //上一行解释说明：例如输出a,b,c;有a b c \0;长度有4，访问C,只用strlen( )-1;
 
  while (left <= right)
  {
    arr2[left] = arr1[left];
    arr2[right] = arr1[right];
    printf("%s\n", arr2);
    Sleep(1000);//睡眠1000秒
    system("cls");//system是库函数，执行系统指令，cls是清除控制台屏幕信息
    right--;
    left++;
  }
  printf("%s\n", arr2);
  return 0;
}

int main()
{
  char arr1[] = "白子寰是一位学习C语言的帅哥!!!";
  char arr2[] = "##############################";
    //两个双引号里的字符内容要对应
 
  int left = 0;
  //int sz = sizeof(arr1) / sizeof(arr1[0]);
  //int right = sz - 2;
  //上两行解释说明：如果是数组的话，arr[]="a,b,c";
  //                             有a b c /0 其元素个数有四个
  //                           而要访问c的话，因为是数组，访问的是其下标，所以sz-2
 
  while (left <= right)
  {
    arr2[left] = arr1[left];
    arr2[right] = arr1[right];
    printf("%s\n", arr2);
    Sleep(1000);   //睡眠1000秒
    system("cls"); //system是库函数，执行系统指令，cls是清除控制台屏幕信息
    right--;
    left++;
  }
  printf("%s\n", arr2);
  return 0;
}

int main()
{
  int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
  int k = 0;//    0 1 2 3 4 5 6 7 8  9
  printf("请输入你要找下标的数字:");
  scanf("%d", &k);
  int i = 0;
  int sz = sizeof(arr) / sizeof(arr[0]);
  for (i = 0; i < sz; i++)
  {
    if (arr[i] == k)
    {
      printf("%d找到了，下标是%d ", k, i);//i访问了数组的下标
      break;
    }
  }
  if (i == sz)
  {
    printf("找不到\n");
  }
  return 0;
}

int main()
{
  int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
  int  k = 0;
  printf("请输入所需找下标的数字:");
  scanf("%d", &k);
  int sz = sizeof(arr) / sizeof(arr[0]);
 
  int left = 0;
  int right = sz - 1;
 
  while (left <= right)
  {
    int mid = (left + right) / 2;
    if (arr[mid] == k)
    {
      printf("%d找到了，下标是%d\n", k, mid);
      break;
    }
    else if (arr[mid] < k)
    {
      left = mid + 1;
    }
    else//中间的元素大于所需要找的元素k，就让右边的=中间的-1；
    {
      right = mid - 1;
    }
  }
  if (left > right)
  {
    printf("%d的下标找不到", k);
  }
 
  return 0;
}

int main()
{
  int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
  int k = 0;
  printf("请输入所需找下标的数字:");
  scanf("%d", &k);
  int sz = sizeof(arr) / sizeof(arr[0]);
 
  int left = 0;
  int right = sz - 1;
  int flag = 0;
 
  while (left <= right)
  {
    int mid = (left + right) / 2;
    if (arr[mid] == k)
    {
      printf("%d找到了，下标为%d\n", k, mid);
      flag = 1;
      break;
    }
    else if (arr[mid] < k)
    {
      left = mid + 1;
    }
    else
    {
      right = mid - 1;
    }
  }
  if (left > right)
  {
    printf("%d找不到它的下标\n", k);
    flag = 0;
  }
  return 0;
}