C ＃ final review programming question (guessed by the teacher)

1. Judge n Odd or even .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            if (n % 2 == 1) Console.WriteLine("{0} It's odd ", n);
            else Console.WriteLine("{0} For the even ", n);
            Console.ReadKey()
;        }
    }
}

2. seek “1-n” Between even numbers and / Odd and .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int sum0 = 0, sum1 = 0;
            for(int i=1;i<=n;i++)
            {
                if (i % 2 == 1) sum0 += i;
                else sum1 += i;
            }
            Console.WriteLine(" Odd and {0}, Even and {1}", sum0, sum1);
            Console.ReadKey();
;        }
    }
}

3. Determine how many uppercase characters there are , Lowercase letters , Numbers , Other characters .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            string s=Console.ReadLine();
            int da = 0, xiao = 0, shuzi = 0, qita = 0;
            for(int i=0;i<s.Length;i++)
            {
                if (s[i] >= 'A' && s[i] <= 'Z') da++;
                else if (s[i] >= 'a' && s[i] <= 'z') xiao++;
                else if (s[i] >= '0' && s[i] <= '9') shuzi++;
                else qita++;
            }
            Console.WriteLine(" Capital {0} individual , Lowercase letters {1} individual , Numbers {2} individual , other {3} individual .", da, xiao, shuzi, qita);
            Console.ReadKey();
;        }
    }
}

4.90-100 good ,80-90 good ,60-80 pass , lower than 60 fail, .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            if (n >= 90 && n <= 100) Console.WriteLine(" good ！");
            else if (n >= 80 && n <= 90) Console.WriteLine(" good ！");
            else if (n >= 60 && n <= 80) Console.WriteLine(" pass ！");
            else Console.WriteLine(" fail, ！");
            Console.ReadKey(); 
;        }
    }
}

5. Define two methods ： An area used to find a circle , A method for finding the area of a rectangle .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        public static double solve(int x)
        {
            return Math.PI * x * x;
        }
        public static int fun(int x,int y)
        {
            return x * y;
        }
        public static void Main(string[] args)
        {
            int r = int.Parse(Console.ReadLine());
            double sum = solve(r);
            Console.WriteLine(" The area of the circle is {0}", sum);
            int a= int.Parse(Console.ReadLine());
            int b= int.Parse(Console.ReadLine()); ;
            int ans = fun(a, b);
            Console.WriteLine(" The area of the rectangle is {0}", ans);
            Console.ReadKey(); 
;        }
    }
}

6. Enter a string , See how many words there are ？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            bool flag = false;
            string s = Console.ReadLine();
            int sum = 0;
            for(int i=0;i<s.Length;i++)
            {
                if (s[i] != ' ')
                {
                    if (flag == false)
                    {
                        sum++;
                        flag = true;
                    }
                    else if (s[i - 1] == ' ') sum++;
                }
            }
            Console.WriteLine(sum);
            Console.ReadKey(); 
;        }
    }
}

7. Enter several grades , Output average score .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int sum = 0;
            for(int i=1;i<=n;i++)
            {
                int x = int.Parse(Console.ReadLine());
                sum += x;
            }
            Console.WriteLine(sum/n);
            Console.ReadKey(); 
;        }
    }
}

8. seek 1-n The number of completions in .（ If a number is exactly equal to the sum of its factors , This number is called “ Complete ”）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int sum = 0;
            for(int i=2;i<=n;i++)
            {
                int flag = 0;
                for(int j=1;j<i;j++)
                {
                    if (i % j == 0) flag += j;
                }
                if (flag == i) Console.WriteLine(i);// If he wants to output numbers , This is changed into sum++; That's it 
            }
            //Console.WriteLine(sum);// There is no need to output the number 
            Console.ReadKey(); 
;        }
    }
}

 9.a Can you divide b？（ Exception handling mechanism ）.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                int a = int.Parse(Console.ReadLine ());
                int b = int.Parse(Console.ReadLine ());
                if (a % b == 0) Console.WriteLine("YES");
                else Console.WriteLine("NO");
            }
            catch
            {
                Console.WriteLine(" Input exception ！");
            }
            Console.ReadKey(); 
;        }
    }
}

10. Given an array , Find the subscript for the first occurrence of a number .

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] a = new int[] { 2, 4, 6, 8, 10, 1, 3, 5, 7, 9 };
            int n = int.Parse(Console.ReadLine());
            int idx = -1;
            for(int i=0;i<a.Length;i++)
            {
                if(a[i]==n)
                {
                    idx = i;
                    break;
                }
            }
            if (idx == -1) Console.WriteLine(" There is no such thing as ");
            else Console.WriteLine(" Subscript to be ：{0}",idx);
            Console.ReadKey(); 
;        }
    }
}

11. Judge whether a number is prime ？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            bool flag = false;
            for(int i=2;i<=n/i;i++)
            {
                if(n%i==0)
                {
                    flag = true;
                    break;
                }
            }
            if (flag == false&&n!=1) Console.WriteLine(" Prime number ");
            else Console.WriteLine(" Not prime ");
            Console.ReadKey(); 
;        }
    }
}

12. Find the sum of an expression ：1！+2！+3！+4！+...n！=？

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int sum = 0;
            int flag = 1;
            int ans = 1;
            while(flag<=n)
            {
                ans *= flag;
                sum += ans;
                flag++;
            }
            Console.WriteLine(sum);
            Console.ReadKey(); 
;        }
    }
}

13.（ Bubble sort 163 Selection sort 171） Sort

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Vijurria
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] a = new int[] { 1, 3, 5, 7, 9, 2, 4, 6, 8, 10 };
            Array.Sort(a);
            for (int i = 0; i < a.Length; i++)
                Console.Write(a[i] + " ");
            Console.ReadKey(); 
;        }
    }
}