Question:

build error in C# (visual studio 8)

by Guest476  |  12 years, 9 month(s) ago

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This is the first time im creating a project using C# and its a course management system in which you can add a student, see the course figures, see students details and withdraw or enrol a student in a particular course and handle their fees etc.

and at the moment when i build the code i get
these three errors which are all basically the same.

Error 1 The type or namespace name 'student' could not be found (are you missing a using directive or an assembly reference?)

Error 2 The type or namespace name 'course' could not be found (are you missing a using directive or an assembly reference?)

Error 3 The type or namespace name 'Scanner' could not be found (are you missing a using directive or an assembly reference?)

Here is my code:

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

namespace Course_Management
{
    class Main
    {
    private static student [] students = new student[320];
    private static course [] courses = new course[5];
    private static int studentCount = 0;
    private static int courseCount = 0;
    private static int repeatDiscount = 0;
    private static int ageDiscount = 0;
    private static Scanner console = new Scanner(System);
  
    public static void main (String [] args)
       {
      char choice;
      String inputLine;
      loadsettingsanddata();

      do
      {
         Console.WriteLine();
         Console.WriteLine("Course Management System");
         Console.WriteLine("~~~~~~~~~~~~~~~~~~~~~~~~~");
         Console.WriteLine("1. Add a Student");
         Console.WriteLine("2. Withdraw a Student");
         Console.WriteLine("3. Display a List of Students for a Course");
         Console.WriteLine("4. Display Course Figures");
         Console.WriteLine("5. Exit");
         Console.WriteLine();
         Console.WriteLine("Enter Option:");

         choice = ' ';
         inputLine = console.nextLine();

         if (inputLine.length() == 1)
            choice = inputLine.charAt(0);

         choice = Character.toUpperCase(choice);

         switch(choice)
         {
            case '1':
                addstudent();
                break;

            case '2':
                withdrawstudent();
                break;
            case '3':
                displaystudents();
                break;
            case '4':
                displaycoursefigures();
                break;

            case '5':
               savesettingsanddata();
               Console.WriteLine("Exiting Program... ");
               Console.WriteLine();
               break;

            default:
               Console.WriteLine("Error!  Thats an Invalid Selection - " +
                                  "Try again please...");
               Console.WriteLine();
         }

      } while (choice != '5');
   }
   /* adding student - Checks whether space is availabe within the desired course
    * then records students details, and updates neccessary figures for the course
    * such as income, and current enrollments
    */
   public static void addstudent()
   {
      String studname;
      String address;
      int age = 0;
      String course_ID;

      student tmpy = null;

      if (studentCount == students.length)
      {
         Console.WriteLine("Error - Students Full!");
         return;
      }

      Console.WriteLine("Enter ID of the Course: ");
      course_ID = console.nextLine();

      int spacesAvail = 0;
      for (int i = 0; i < courseCount; i++)
             {
                 if (courses[i].courseID.equalsIgnoreCase(course_ID))
                 {
                     spacesAvail = courses[i].checkSpaceAvail();
                 }
             }
         if (spacesAvail > 0)
         {
                 Console.WriteLine("Spaces Available: " + spacesAvail);
                 Console.WriteLine("Enter Student's Name: ");
              studname = console.nextLine();

              Console.WriteLine("Enter Student's Address: ");
              address = console.nextLine();
              if (address.equalsIgnoreCase("Enter Students Address: "))
              {
                  address = "Address Unknown";
              }
              Console.WriteLine("Enter Student's Age: ");
              age = Convert.ToInt16(entry);

              if (console.hasNextLine())
                console.nextLine();
              int feeOwing = calFees(course_ID);
              Console.WriteLine("Fees Owing: " + feeOwing);
              int rptdiscount = 0;
              String repeatingStudent = repeatStudent(studname);
              if (repeatingStudent.equals("Y"))
              {
                  rptdiscount = (feeOwing/100)* repeatDiscount;
              }else
              {
                  rptdiscount = 0;
              }
              int adiscount = 0;
              int newFees = feeOwing - rptdiscount - adiscount;
              Console.WriteLine("Repeat Discount: " + rptdiscount);
              Console.WriteLine("Age Discount: " + adiscount);
              Console.WriteLine("New Fees Owing: " + newFees);
              tmpy[counter] = new Student(course_ID, studname, address, age, feeOwing, 0, rptdiscount, adiscount);
              students[studentCount] = tmpy;
              studentCount++;
              for (int i = 0; i < courseCount; i++)
                     {
                         if (courses[i].courseID.equalsIgnoreCase(course_ID))
                         {
                             courses[i].adjustcourseincome(feeOwing,rptdiscount,adiscount);
                         }
                     }
         }else
         {
             Console.WriteLine("There are no spaces available in this Course");
         }
   }
   /* calculate course fee - retrieves the fees for selected course
    */
   public static int calFees(String courseID)
   {
           int fees = 0;
           for (int i = 0; i < courseCount; i++)
             {
                 if (courses[i].courseID.equalsIgnoreCase(courseID))
                 {
                     fees = courses[i].getChargeStudent();
                 }
             }
           return fees;
   }
   /* repeating student - determines whether the student being added is a repeat student,
    * so that the discount can be applied for the student
    */
   public static String repeatStudent(String name)
   {
           String repeatingStud = "N";
           for (int i=0; i < studentCount; i++)
           {
               if (students[i].studName.equalsIgnoreCase(name))
               {
                   repeatingStud = "Y";
               }
           }
           return repeatingStud;
   }
   /* withdraw student - checks that a valid course code is enters, then checks to see whether
    * the entered student has been enrolled in that course. If so, then the amount that should
    * be refunded to the student. Also updates the course details, such as income and the
    * number of students enrolled in the course.
    */
   public static void withdrawstudent()
   {
           String stuName;
           String course_ID;
           String addy = "";
           int age = 0;
           String corsName = "";
           String Scourse = "";
           String ans = "";
           Console.WriteLine("Enter the Course Id: ");
           course_ID = console.nextLine();
           int crecnum = 0;
           for (int i = 0; i < courseCount; i++)
           {
                if (courses[i].courseID.equalsIgnoreCase(course_ID))
                 {
                     corsName = courses[i].getCourseName();
                     crecnum = i;
                 }
           }
           if (corsName.equals("")){
                 Console.WriteLine("Error! Course not found, unable to withdraw student");
           }else
           {
               Console.WriteLine("Enter Student's Name: ");
               stuName = console.nextLine();
               int srecnum = 0;
               for (int i = 0; i < studentCount; i++)
              {
                  if (students[i].studName.equalsIgnoreCase(stuName))
                  {
                      if (students[i].courseID.equalsIgnoreCase(course_ID))
                      {
                          addy = students[i].getAddress();
                          age = students[i].getAge();
                          srecnum = i;
                      }
                  }
                }
               if (age == 0)
               {
                   Console.WriteLine("Error! Unable to withdraw student, student was not found in this course.");
               }else
               {
                     Console.WriteLine("Withdrawing Student: " + stuName + ", " + addy + ", " + age);
                     Console.WriteLine("From Course " + corsName);
                Console.WriteLine("Correct? Continue?(Y/N) :");
                ans = console.nextLine();
                if (ans.equalsIgnoreCase("Y"))
                {
                    students[srecnum].withdrawstudent();
                    int refund = students[srecnum].getAmtPaid();
                    int feeOwing = students[srecnum].getFeesOwing();
                    int rptDiscount = students[srecnum].getRDiscount();
                    int aDiscount = students[srecnum].getADiscount();
                    courses[crecnum].withdrawadjustment(feeOwing, rptDiscount,aDiscount);
                    Console.WriteLine("Amount to be refunded to student: " + refund);
                }
                 }
           }
   }
   /* display students - displays the students currently enrolled within the required
    * course. If no students enrolled, then message displayed.
    */
   public static void displaystudents()
   {
         if (studentCount > 0)
         {
               String courseID;
               Console.WriteLine("Enter Course ID: ");
             courseID = console.nextLine();
             Console.WriteLine();
            
             for (int i = 0; i < courseCount; i++)
             {
                 if (courses[i].courseID.equalsIgnoreCase(courseID))
                 {
                     courses[i].printstudentlist(courseID);
                 }
             }
          for (int i = 0; i < studentCount; i++)
          {
                  if (students[i].courseID.equalsIgnoreCase(courseID))
                  {
                      students[i].print();
                  }
            }
         }else
         {
             Console.WriteLine();
             Console.WriteLine("Error! There hasn't been any students added, unable to display list");
             Console.WriteLine();
         }
   }
   /* displays figures for each course
    */
   public static void displaycoursefigures()
   {
           Console.WriteLine();
           for (int i = 0; i < courseCount; i++)
           {
               courses[i].printcoursefigures();
           }
   }
   /*controls the loading of data when application started
    */
   public static void loadsettingsanddata()
   {
           Console.WriteLine("Loading Data");
           loadcourses();
           loadstudents();
           loaddiscounts();
   }
   /* load courses from file to be used while application is being used.
    */
   public static void loadcourses()
   {
           String ID;
           String name;
           String group;
           String tname;
           int stuenrolled;
           int stumax;
           int stucharge;
           int corscost;
           int cpstud;
           String inputLine;
           course tmpy = null;
           StreamReader SR;
  try
       {
            SR = File.OpenText("courselist.txt");
            inputLine = SR.ReadLine();
            while (inputLine != null) {
            ID = inputLine;
            inputLine = br.readLine();
            name = inputLine;
            inputLine = br.readLine();
            group = inputLine;
            inputLine = br.readLine();
            tname = inputLine;
            inputLine = br.readLine();
            stuenrolled = Integer.parseInt(inputLine);
            inputLine = br.readLine();
            stumax = Integer.parseInt(inputLine);
            inputLine = br.readLine();
            stucharge = Integer.parseInt(inputLine);
            inputLine = br.readLine();
            corscost = Integer.parseInt(inputLine);
            inputLine = br.readLine();
            cpstud = Integer.parseInt(inputLine);
            tmpy[counter] = new course(ID, name, group, tname,stuenrolled, stumax, stucharge,corscost, cpstud, 0);
            courses[courseCount] = tmpy;
            courseCount++;
            inputLine = br.readLine();
        }
        br.close();

      }
      catch (IOException exc)
{
    Console.WriteLine(exc.Message + "\nError Opening File");
    return;
      }
   }
   /* loads student details from file to be used while application being run
    */
   public static void loadstudents()
   {
           String ID;
           String name;
           String addy;
           int age;
           int feeOwing;
           int amtPaid;
           int rptDiscount;
           int aDiscount;
           String inputLine;
           student tmpy = null;
           StreamReader SR;
    try
         {
                SR = File.OpenText("studentlist.txt");
                inputLine = SR.ReadLine();
                while (inputLine != null) {
                ID = inputLine;
                inputLine = br.readLine();
                name = inputLine;
                inputLine = br.readLine();
                addy = inputLine;
                inputLine = br.readLine();
                age = Integer.parseInt(inputLine);
                inputLine = br.readLine();
                feeOwing = Integer.parseInt(inputLine);
                inputLine = br.readLine();
                amtPaid = Integer.parseInt(inputLine);
                inputLine = br.readLine();
                rptDiscount = Integer.parseInt(inputLine);
                inputLine = br.readLine();
                aDiscount = Integer.parseInt(inputLine);
            tmpy[counter] = new student(ID, name, addy, age, feeOwing,amtPaid,rptDiscount , aDiscount);
            students[studentCount] = tmpy;
            studentCount++;
            for (int i = 0; i < courseCount; i++)
                 {
                     if (courses[i].courseID.equals(ID))
                     {
                         courses[i].adjustcourseincome(feeOwing,rptDiscount,aDiscount);
                     }
                 }
            inputLine = br.readLine();
        }
        br.close();

    }
catch (IOException exc)
{
    Console.WriteLine(exc.Message + "\nError Opening File");
    return;
}
   }
   /* loads settings from file, the percentage for repeating students, the age at which
    * the age discount should be applied and the discount given when students meets the age
    * discount. This is stored within a file, so that should a change be required then changes
    * to the actual application is not required.
    */
   public static void loaddiscounts()
   {
           String inputLine;
           StreamReader SR;
    try
        {
            SR = File.OpenText("discounts.txt");
            inputLine = SR.ReadLine();
            while (inputLine != null) {
            repeatDiscount = Integer.parseInt(inputLine);
            inputLine = br.readLine();
            ageStartDiscount = Integer.parseInt(inputLine);
            inputLine = br.readLine();
            ageDiscount = Integer.parseInt(inputLine);
            inputLine = br.readLine();
        }
        br.close();

        }
      catch (IOException exc)
    {
    Console.WriteLine(exc.Message + "\nError Opening File");
    return;
    }
   }
   /* controls the saving of data to file
    */
   public static void savesettingsanddata()
   {
           Console.WriteLine();
           Console.WriteLine("Backing up data");
           Console.WriteLine();
           writecoursefiles();
           writestudentfiles();
   }
   /* writes all course details to file, so that they have been saved for
    * when the application is next run.
    */
   public static void writecoursefiles()
   {
           PrintWriter pw = new PrintWriter(
                              new BufferedWriter(
                                new FileWriter("courselist.txt")));
        int studentsEnrolled = 0;                        
        for (int i = 0; i< courseCount; i++)
        {
            pw.println(courses[i].getCourseId());
            pw.println(courses[i].getCourseName());
            pw.println(courses[i].getCoursegroup());
            pw.println(courses[i].getTeachersName());
            pw.println(studentsEnrolled);
            pw.println(courses[i].getMaxStudents());
            pw.println(courses[i].getChargeStudent());
            pw.println(courses[i].getCourseRunningCost());
            pw.println(courses[i].getCoursePStudent());
        }
        pw.close();
   }
   /* writes all student details to file for use when application is next used.
    * does not save data of withdrawn students, via this these details are removed from
    * the system.
    */
   public static void writestudentfiles()
   {
           PrintWriter pw = new PrintWriter(
                              new BufferedWriter(
                                new FileWriter("studentlist.txt")));
        for (int i = 0; i< studentCount; i++)
        {
            if (!students[i].courseID.equalsIgnoreCase("---"))
            {
                pw.println(students[i].getCourseID());
                pw.println(students[i].getStudName());
                pw.println(students[i].getAddress());
                pw.println(students[i].getAge());
                pw.println(students[i].getFeesOwing());
                pw.println(students[i].getAmtPaid());
                pw.println(students[i].getRDiscount());
                pw.println(students[i].getADiscount());
            }
        }
        pw.close();
   }
}
        }

Your help would be greatly appreciated as i have to hand in the application to my boss tomorrow.

Cheers

Mishka

 Tags: build, C#, Error, Studio, Visual

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1 ANSWERS

  1. Jessica_Nancy
    The errors are obvious. You have not declared the classes student,course and Scanner in your code. Declare these classes.

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