c#认证考试试题。

1.1、输入一个正整数n,如果是偶数则求n以内的所有偶数和,奇数则求n以内的所有奇数的和。

static void Main(string[] args)
{
int result=0;
Console.WriteLine("请输入一个正整数:");
int n = Convert.ToInt32(Console.ReadLine());
if(n%2==0)
{
for (int i = 0; i <= n; i++)
if (i % 2 == 0)
result += i;
}
else
{
for (int i = 0; i <= n; i++)
if (i % 2 != 0)
result += i;
}
Console.WriteLine("result为:{0}",result);
Console.ReadLine();

}

1.2、输入一个正整数,输出所有约数。

static void Main(string[] args)
{
Console.WriteLine("请输入一个正整数:");
int n = Convert.ToInt32(Console.ReadLine());
if (n % 2 == 0)
{
for (int i = 2; i <= n / 2; i++)
{
if (n % i == 0)
{
Console.WriteLine(i);
}
}
}
else
{
for(int i=3;i<=(n-1)/2;i++)
{
if(n%i==0)
{
Console.WriteLine(i);
}
}
}
Console.ReadLine();
}

1.3-1.4、输入两个正整数,求最大公约数,最小公倍数.

static void Main(string[] args)
{
int result=1;
Console.WriteLine("请输入第一个正整数:");
int a = Convert.ToInt32(Console.ReadLine());
int x = a;
Console.WriteLine("请输入第二个正整数:");
int b = Convert.ToInt32(Console.ReadLine());
int y = b;
if (a > b)
{
int t = a;
a = b;
b = t;

}
while(true)
{

if (b % a == 0)
{
result = a;
break;
}
else
{
int ys = b % a;
b = a;
a = ys;
}

}
int result1 = x * y / result;
Console.WriteLine("最大公约数为:{0}",result);
Console.WriteLine("最小公倍数为:{0}", result1);
Console.ReadLine();
}

1.5、判断素数。

static void Main(string[] args)
{
bool prime=true;
Console.WriteLine("请输入一个正整数:");
int n = Convert.ToInt32(Console.ReadLine());
for(int i=2;i<=n/2;i++)
{
if (n % i == 0)
prime = false;
break;
}
if (prime)
Console.WriteLine("{0}是素数", n);
else
Console.WriteLine("{0}不是素数", n);
}

1.6、

1.7、验证15位身份证并判断身份证主人性别

static void Main(string[] args)
{
Console.WriteLine("请输入15位身份证号码:");
string id = Convert.ToString(Console.ReadLine());
char ch;

if(id.Length<15||id.Length>15)
{
Console.WriteLine("号码格式不正确!");

}
else
{

for(int i=0;i<id.Length;i++)
{
ch = id[i];
if (!(ch>='0'&&ch<='9'))
{
Console.WriteLine("号码格式不正确!");
break;
}


}
if (id[id.Length-1] % 2 == 0)
Console.WriteLine("性别为女!");
else
Console.WriteLine("性别为男!");
}

Console.ReadLine();
}

1.9、求字符串中ASCII最大的字符

static void Main(string[] args)

        {

            Console.WriteLine("请输入一个字符串:");

            string s_text = Convert.ToString(Console.ReadLine());

            char ch ;

            ch = s_text[0];

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

            {

                if (ch < s_text[i])

                    ch = s_text[i];

            }

            Console.WriteLine("ASCII最大的字符是{0}",ch);

            Console.ReadLine();

        }

1.10、求字符串中ASCII最小的字符

static void Main(string[] args)

        {

            Console.WriteLine("请输入一个字符串:");

            string s_text = Convert.ToString(Console.ReadLine());

            char ch;

            ch = s_text[0];

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

            {

                if (ch > s_text[i])

                    ch = s_text[i];

            }

            Console.WriteLine("ASCII最小的字符是{0}", ch);

            Console.ReadLine();

        }

1.11、输入原字符串和密钥字符串,输出对字符串进行加密的结果。

static void Main(string[] args)
{
string s_text, s_key;
string s_result = null;
char ch;
Console.WriteLine("请输入原字符串:");
s_text =Convert.ToString( Console.ReadLine());
Console.WriteLine("请输入密钥字符串:");
s_key = Convert.ToString(Console.ReadLine());
if (s_text.Length != s_key.Length)
{
Console.WriteLine("密钥字符串与原字符串长度必须相等!");
}
else
{
for(int i=0;i<s_text.Length;i++)
{
ch = s_text[i];
s_result += ch ^ s_key[i];

}
Console.Write("加密后的字符串为:");

}
Console.WriteLine(s_result);
Console.ReadLine();
}

2.1继承与派生

public class Animal
{
private bool m_sex;
private int m_age;
public bool Sex
{
get { return m_sex; }
set { m_sex = value; }
}

public int Age
{
get { return m_age; }
set { m_age = value; }
}
public Animal()
{
Sex = false;
}
public virtual string Introduce()
{
if (Sex)
return "This is a male Animal!";
else
return "This is a female Animal!";
}

}
public class Dog:Animal
{
public Dog()
{
Sex = true;
}
public override string Introduce()
{
if (Sex)
return "This is a male Dog!";
else
return "This is a female Dog!";
}
}
public class Cat:Animal
{

public override string Introduce()
{
if (Sex)
return "This is a male Cat!";
else
return "This is a female Cat!";
}
}

static void Main(string[] args)
{
Animal animal = new Animal();
Console.WriteLine(animal.Introduce());
Dog dog = new Dog();
Console.WriteLine(dog.Introduce());
Cat cat = new Cat();
Console.WriteLine(cat.Introduce());
}

2.11

public class Animal
{
private bool m_sex;
private string m_sound;
public bool Sex
{
get { return m_sex; }
set { m_sex = value; }
}
public Animal()
{
Sex = false;
Sound = "How1...";
}
public string Sound
{
get { return m_sound; }
set { m_sound = value; }
}
public virtual string Roar()
{
return Sound;
}
}
public class Dog:Animal
{
public Dog()
{
Sex = true;
Sound = "Wow...";
}
public override string Roar()
{
return "Dog:"+Sound;
}
}
public class Cat:Animal
{
public Cat()
{
Sound = "Miaow...";
}
public override string Roar()
{
return "Cat:"+Sound;
}
}
public class Cow:Animal
{
public Cow()
{
Sound = "Moo...";
}
public override string Roar()
{
return "Cow:" + Sound;
}
}

static void Main(string[] args)
{
Animal animal;
Dog dog = new Dog();
animal = dog;
Console.WriteLine(animal.Roar());
Cat cat = new Cat();
animal = cat;
Console.WriteLine(animal.Roar());
Cow cow = new Cow();
animal=cow;
Console.WriteLine(animal.Roar());
}

原文地址:https://www.cnblogs.com/-sbz/p/7532185.html