c#程序开发案例课堂第六章作业答案

习题

习题.jpg

练习1

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

namespace practise1
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] MyArray = new int[10];
            int Sum = 0;
            for(int i=0;i<10;i++)
            {
                MyArray[i] = i; //为数组赋值
            }

            for(int i=0;i<10;i++)
            {
                if(MyArray[i]%2==0)//取偶数
                {
                    Sum += MyArray[i];//求和
                }
            }
            Console.WriteLine(Sum);
        }
    }
}

练习2

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

namespace practise2
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] x = new int[5] { 4, 2, 1, 6, 5 };
            int[] y = new int[5];
            foreach (int i in x)
                Console.Write(i);//输出x
            Console.WriteLine("\n");
            Array.Reverse(x);//颠倒x的顺序
            y = (int[])x.Clone();//将颠倒之後的数据复制到y中
            foreach (int i in y)
                Console.Write(i);//输出y
        }
    }
}

练习3

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections;//添加命名空间以使用ArryList

namespace practise3
{
    class Program
    {
        static void Main(string[] args)
        {
            ArrayList MyArrylist = new ArrayList(4);//创建ArryList对象
            string Result = null;//为以后输出结果做准备

            //利用add对象为其添加元素
            MyArrylist.Add("Yuki");
            MyArrylist.Add("17721528");
            MyArrylist.Add("Hablee");

            foreach (string element in MyArrylist)
                Console.WriteLine(element + " ");

            Console.WriteLine();

            //使用Contains查找元素并输出结果
            Console.WriteLine(MyArrylist.Contains("Yuki"));

        }
    }
}

练习4

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

namespace practise4
{
    public class students
    {
        public string Name;
        public string Id;
        public char Sex;
        public double Grades;

    }
    
    class Program
    {
        static void Main(string[] args)
        {
            students stus1 = new students();
            stus1.Name = "Hablee";
            stus1.Id = "17721528";
            stus1.Sex = 'M';
            stus1.Grades = 90.5;

            students stus2 = new students();
            stus2.Name = "Yuki";
            stus2.Id = "17721567";
            stus2.Sex = 'F';
            stus2.Grades = 97.5;

            List<students> Students = new List<students>();//使用List<T>进行存储
            Students.Add(stus1);
            Students.Add(stus2);//增加操作
            Console.WriteLine($"增加後: ");
            foreach (students stu in Students)
                Console.WriteLine($"{stu.Name}\t{stu.Id}\t{stu.Sex}\t{stu.Grades}");
            //遍历操作

            Console.WriteLine();
            Students.Remove(stus1);//删除操作
            Console.WriteLine($"删除後: ");
            foreach (students stu in Students)
                Console.WriteLine($"{stu.Name}\t{stu.Id}\t{stu.Sex}\t{stu.Grades}");

            Console.WriteLine();
            Console.WriteLine(Students.Contains(stus1));//访问操作

        }
    }
}

练习5

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


namespace practise4
{
    public class Students
    {
        public string Name;
        public string Id;
        public char Sex;
        public double Grades;

    }

    class Program
    {
        static void Main(string[] args)
        {            
            Dictionary<string, Students> students = new Dictionary<string, Students>();
            //实例化一个Dictionary为students，使用Dictionary<k,v>进行存储

            //增加学生信息
            Students stu1 = new Students();//实例化一个学生
            stu1.Name = "Hablee";
            stu1.Id = "17721528";
            stu1.Sex = 'M';
            stu1.Grades = 90.5;
            students.Add("Hablee", stu1);

            Students stu2 = new Students();//实例化另外一个学生
            stu2.Name = "Yuki";
            stu2.Id = "17721567";
            stu2.Sex = 'F';
            stu2.Grades = 97.5;
            students.Add("Yuki", stu2);

            Console.WriteLine($"增加後: ");
            foreach (KeyValuePair<string, Students> valuePair in students)
                Console.WriteLine($"{valuePair.Key}的信息\t{valuePair.Value.Id}\t{valuePair.Value.Name}\t" +
                    $"{valuePair.Value.Sex}\t{valuePair.Value.Grades}");
            //遍历操作

            Console.WriteLine();
            students.Remove("Hablee");//删除操作
            Console.WriteLine($"删除後: ");
            foreach (KeyValuePair<string, Students> valuePair in students)
                Console.WriteLine($"{valuePair.Key}的信息\t{valuePair.Value.Id}\t{valuePair.Value.Name}\t" +
                    $"{valuePair.Value.Sex}\t{valuePair.Value.Grades}");
            //遍历操作

            Console.WriteLine();
            Console.WriteLine(students.ContainsKey("Yuki"));
            Console.WriteLine(students.ContainsKey("Hablee"));//访问操作，判断是否还在

        }
    }
}

以上代码均在visual studio 2017中编译通过并运行成功

题外话：感觉Dictionary<k,v>比List<T>要好用那么一丢丢，可能本人水平不够，无法用到List<T>的精髓。