#include<stdio.h>
/*计算N的阶乘*/
int main()
{
int n = 0;
int i = 0;
int sum = 1;
printf("请输入一个数字：\n");
scanf_s("%d",&n);
for (i = 1; i <= n; i++)
{
sum = sum * i;
}
printf("sum=:%d\n",sum);
return 0;
}
/*计算1!+2！+3！+4！+5！+....+10!*/
int main()
{
int b = 1;
int i = 0;
int sum = 0;
for (i = 1; i <= 10; i++)
{
b = b *i;
sum = sum + b;
}
printf("10的阶乘和为：%d\n",sum);
return 0;
}
/*寻找有序序列中的想要找的元素*/
int main()
{
int arr[] = {1,2,3,4,5,6,7,8,9,10};
int left = 0;//左下标
int sz = sizeof(arr)/sizeof(arr[0]);//计算元素个数
int right = sz-1 ;//右下标
int k = 7;
while (left<=right)
{
int mid = (left + right) / 2;//中间下标
if (arr[mid] < k)
{
left = mid+1;
}
else if (arr[mid] > k)
{
right = mid-1 ;
}
else{
printf("找到了，下标为：%d\n", mid);
break;
}
}
if (left > right)
{
printf("找不到\n");
}
return 0;
}
#include<string.h>
#include<windows.h>
#include<stdlib.h>
int main()
{
char arr1[] = "welcome to bit !!!!!!!!";
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);
system("cls");//执行系统命令的一个函数cls--清空屏幕
left++; right--;
}
printf("%s\n", arr2);
return 0;
}
//密码登录。输入密码，正确一次则退出，三次都输入错误则退出
#include<string.h>
int main()
{
char password[20] = {0};
int i = 0;
for (i = 0; i < 3; i++)
{
printf("请输入密码：");
scanf_s("%s", password);
if (strcmp(password ,"123456") == 0)//等号不能用来判断两个字符串是否相等
{
printf("密码正确\n");
break;
}
else{
printf("密码错误\n");
}
}
if (i == 3)
{
printf("重新登陆\n");
}
return 0;
}
