do while ()循环

do

循环语句;

while(表达式);

句式结构：

执行过程：

do while循环的特点：

代码练习：

二分法算法：

int main()
{int arr[] = { 0,1,2,3,4,5,6,7,8,9};int k = 7;//查找数字7，在arr这个数组中查找k(7)的值int n=sizeof(arr) / sizeof(arr[0]);//数组总大小/数组单个元素的大小=数组的元素数量int left = 0;int right = n - 1;while (left <= right){int mid = (left + right) / 2;//数组元素中间值arr[4]if (arr[mid] < k){left = mid + 1;//范围舍去左边一半，从arr[5]开始}else if (arr[mid] > k){right = mid - 1;//范围舍去右半边，到arr[3]结束}else{printf("找到了，下标是%d", mid);break;}}if (left > right){printf("找不到\n");}return 0;
}

#include <string.h>
#include <windows.h>int main()
{char arr1[] = { "I love mum and dad" };char arr2[] = { "##################" };int left = 0;int right = strlen(arr1) - 1;while (left <= right){arr2[left] = arr1[left];arr2[right] = arr1[right];printf("%s\n", arr2);Sleep(1000);//睡眠1秒system("cls");//清空屏幕left++;right--;}printf("%s\n", arr2);return 0;
}

---

#include <string.h>
int main()
{int i = 0;//假设正确的密码是字符串“123456”char password[20] = { 0 };for (i = 0; i < 3; i++){printf("请输入密码:>");scanf("%s", password);//因为password是数组名，数组名就是地址，so无需取地址//if (password == "123456")//err-两个字符比较，不能使用==，应该使用strcmpif (strcmp(password, "123456") == 0)//strcmp比较的是每一位的ASCII值{printf("登录成功\n");break;}elseprintf("密码错误,重新输入\n");}if (i == 3)printf("三次密码均错误，退出程序\n");return 0;
}