C#课后习题答案

1、编写程序（输入一个华氏温度，输出一个摄氏温度。公式C=(F-32)*5/9）

static void Main(string[] args)

{

Console.WriteLine("请输入华氏温度：");

double f = double.Parse(Console.ReadLine());

double c = (f - 32) * 5 / 9;

Console.WriteLine("对应摄氏温度为：" + c);

Console.ReadLine();

}

2、编写一个C#控制台应用程序，对于输入的正整数n，计算1!+2!+3!+…+n!的值并输出结果。

public int fn(int n)

{

int sum = 0, m = 1;

for (int i = 1; i <= n; i++)

{

m = m * i;

sum += m;

}

return sum;

}

3、编写程序，输入一个整数，将其各位数字颠倒顺序后输出

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication1

{

class Program

{

static void Main(string[] args)

{

int t = 0;

try

{

t = int.Parse(Console.ReadLine());

}

catch (Exception ee)

{

Console.WriteLine(ee.Message);

return;

}

string s = t.ToString();

for (int i = s.Length-1; i>=0; i--)

{

Console.Write(s[i]);

}

Console.Read();

}

}

}

4、C#写一个输入三个整数，按大到小顺序输出的小程序

int[] arr = new int[3];

for (int i = 0; i < arr.Length; i++)

{

Console.WriteLine("请输入第" + (i + 1) + "个数");

arr[i] = Convert.ToInt32(Console.ReadLine());

}

for (int i = 0; i < arr.Length - 1; i++)

{

for (int j = 0; j < arr.Length - 1 - i; j++)

{

if (arr[j] < arr[j + 1])

{

int temp = arr[j];

arr[j] = arr[j + 1];

arr[j + 1] = temp;

}

}

}

for (int i = 0; i < arr.Length; i++)

{

Console.WriteLine(arr[i]);

}

5、编写程序,输入年份和月份,输出该年该月的天数

int y, m, d; //定义三个变量,分别用来接收年月日int sum = 0, count = 0; //sum统计总天数,count储存天数int total = 0; //储存输入月份后有多少天

y = Convert.ToInt32(txtYear.Text); //强制类型转换

m = Convert.ToInt32(txtMonth.Text); //

d = Convert.ToInt32(txtDays.Text); //

switch (m) //输入月份后获得该月天数

{

case 1:

case 3:

case 5:

case 7:

case 8:

case 10:

case 12:

total = 31;

break;

case 4:

case 6:

case 9:

case 11:

total = 30;

break;

case 2:

if ((y % 100 != 0) && (y % 4 == 0) || (y % 400 == 0))

{

total = 29;

}

else

{

total = 28;

}

break;

}

if (d > total ) //如果输入2010 2 29就会出错{

txtXianShi.Text = "该天不存在";

}

else

{

if (y >= 1 && y <= 9999)

{

if (m >= 1 && m <= 12)

{

for (int i = 1; i <= m; i++) //循环累加天数

{

switch (i)

{

case 1:

case 3:

case 5:

case 7:

case 8:

case 10:

case 12:

count = 31;

break;

case 4:

case 6:

case 9:

case 11:

count = 30;

break;

case 2:

if ((y % 100 != 0)&&(y % 4 == 0)||(y % 400 == 0))

{

count = 29;

}

else

{

count = 28;

}

break;

}

sum = sum + count; //循环一次累加一个月的天数}

txtXianShi.Text = sum.ToString(); //类型转换后输出

}

{

txtXianShi.Text = "你输入的年份不正确！请重新输入！";

}

}

else

{

txtXianShi.Text = "你输入的月份不正确！请重新输入！";

}

}

6、求公式1/2+3/2+5/3+8/5+13/8+21/13+.....中前20项的和

#include

intmain()

{

doublea = 2.0,b = 1.0;

doublesum = 0.0;

inti = 0;

while( i < 20 )

{

sum += a / b;

doubletemp = b;

b = a;

i++;

}

printf("sum = %lf\n",sum);

return0;

}

7、鸡兔同笼,鸡兔共30只,脚90只,计算共多少只鸡多少只兔#include

main(){

int chicken, rabbit;

int legs = 90, sum = 30;

rabbit = (90-30*2)/2;

chicken = 30 - rabbit;

printf("%d只兔子，%d只鸡", rabbit, chicken);

}

8、编辑程序，求1~100之间的所有质数

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication10

{

class Program

{

static void Main(string[] args)

{

int min, max, i, j, n;

bool flag;

Console.WriteLine(" 素数\n");

Console.WriteLine(" 输入范围的下限（不小于2）");

min = Convert.ToInt16(Console.ReadLine());

Console.WriteLine(" 输入范围的上限");

max = Convert.ToInt16(Console.ReadLine());

n = 0; //初始化素数的个数为0

for (i = min; i <= max;i++ ) //i为min到max之间的所有自然数

{

flag = true; //设置为真

for (j = 2; j <= Math.Sqrt(i);j++ )

{

if (i % j == 0) //如果i能被j整除

{

flag = false; //设置标记为假

break; //退出内循环

}

}

if (!flag) //如果标记为假

{ continue; } // 退出本次循环

Console.Write("{0,6}",i); //输出素数

n++; /素数递增

if(n%10==0) //没输出十个素数换一次行

{

Console.WriteLine();

}

}

Console.WriteLine("\n {0}到{1}之间的素数共有{2}",min,max,n);

Console.ReadLine();

}

}

}

9、编写程序,显示10个单项选择题,用户选择答案并提交后给出分数

(1)在设计中拉十个RadioButton控件和一个Button控件。双击Button控件，写入以下代码！protected void Button1_Click(object sender, EventArgs e)

{

int n=0;

int i=0;

if(RadioButton1.Checked==true)

{

n=n+10;

i++;

}

if(RadioButton2.Checked==true)

{

n=n+10;

i++;

}

........

if(RadioButton10.Checked==true)

{

n=n+10;

i++;

}

}

你将n打出来它就是你要的分数,而i就是正确答案的个数

(2)Gridview中的RadioButton

在Gridview中放了一个radiobutton组

SelectCommand="SELECT [Answer_A], [Answer_B], [Answer_C], [Answe_D], [Answe_Key], [Ques_Squc], [Ques_Title] FROM [Ques_Info] WHERE ([File_ID] = @File_ID) ORDER BY [Ques_Squc]">