CODEWITHSUNDEEP
c#listdictionaryfor-loop
user9482565
user9482565

Reputation:

For Loop with Dictionary / List Not Counting

My inner most nested for loop is not counting correctly. It turns into an infinite loop and I'm not seeing why. Does it have something to do with

studentScores.Add(intScore);

being inside the nested for loop?

class Program
{
    static void Main(string[] args)
    {
        string studentCount = string.Empty;
        string examCount = string.Empty;

        Console.WriteLine("Please enter the number of students you will enter.");
        studentCount = Console.ReadLine();
        int totalStudents = Convert.ToInt32(studentCount);

        Console.WriteLine(string.Empty);
        Console.WriteLine("Please enter the number of exams to be entered for each student.");
        examCount = Console.ReadLine();
        int totalExams = Convert.ToInt32(examCount);
        Console.WriteLine(string.Empty);

        Dictionary<int, List<int>> studentMap = new Dictionary<int, List<int>>();
        List<int> studentScores = new List<int>();

        for (int students = 0; students < totalStudents; students++)
        {
            for (int scores = 0; scores < totalExams; scores++)
            {
                string score = string.Empty;
                Console.WriteLine("Enter exam");
                score = Console.ReadLine();
                int intScore = Convert.ToInt32(score);
                studentScores.Add(intScore);
            }
        }
    }
}

Upvotes: 0

Views: 97

Answers (3)

cse
cse

Reputation: 4104

You can use following code snippet. See here for full working code:

Dictionary<int, List<int>> studentMap = new Dictionary<int, List<int>>();

for (int students = 0; students < totalStudents; students++)
{
    //Create List<int> here for each student
    List<int> studentScores = new List<int>(); 
    for (int scores = 0; scores < totalExams; scores++)
    {
       //Read and save scores of student in each subject
        string score = string.Empty;
        Console.WriteLine("Enter exam");
        score = Console.ReadLine();
        int intScore = Convert.ToInt32(score);
        studentScores.Add(intScore);
    }

    //Add this in dictonary. Key as the `index` and 
    //value as the scores saved in `studentScores`
    studentMap.Add(students, studentScores);
}

Upvotes: 1

sujith karivelil
sujith karivelil

Reputation: 29026

As per the clarifications that you provided in the comment, you should try something like this:

Dictionary<int, List<int>> studentMap = new Dictionary<int, List<int>>();
for (int student = 0; student < totalStudents; student++)
{
    studentMap.Add(student, new List<int>());
    for (int scores = 0; scores < totalExams; scores++)
    {
        string score = string.Empty;
        Console.WriteLine("Enter exam");
        score = Console.ReadLine();
        int intScore = Convert.ToInt32(score);
        studentMap[student].Add(intScore);
    }
}

Upvotes: 0

mjwills
mjwills

Reputation: 23898

List<int> studentScores = new List<int>();

for (int students = 0; students < totalStudents; students++)
{
    for (int scores = 0; scores < totalExams; scores++)
    {
        string score = string.Empty;
        Console.WriteLine("Enter exam");
        score = Console.ReadLine();
        int intScore = Convert.ToInt32(score);
        studentScores.Add(intScore);
    }
}

should likely be:

for (int students = 0; students < totalStudents; students++)
{
    List<int> studentScores = new List<int>();
    for (int scores = 0; scores < totalExams; scores++)
    {
        string score = string.Empty;
        Console.WriteLine("Enter exam");
        score = Console.ReadLine();
        int intScore = Convert.ToInt32(score);
        studentScores.Add(intScore);
    }
    studentMap[students] = studentScores;
}

This will mean each entry in the Dictionary will have a subset of the studentScores data. This is different to your existing code, which lumps all of the studentScores data in a single List.

Upvotes: 1

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