Kitchen

using System;

namespace StudentScores
{
    class Program
    {
        static void Main ( string[] args )
        {
            int[,] StudentScores = new int[20, 4];

            for ( int i = 0; i < 20; i++ )
            {
                for ( int j = 0; j < 4; j++ )
                {
                    Console.Write( "Student {0}, exam {1} score: ", i + 1, j + 1 );

                    try
                    {
                        StudentScores[i, j] = Convert.ToInt32( Console.ReadLine() );
                    }
                    catch
                    {
                        Console.WriteLine( "Invalid score, please re-enter it." );
                        j -= 1;
                    }
                }
            }


            Console.WriteLine( "\n\nStudent X: Exam 1; Exam 2; Exam 3; Exam 4; Exam Average\n" );

            int Exam1Sum = 0;
            int Exam2Sum = 0;
            int Exam3Sum = 0;
            int Exam4Sum = 0;

            for ( int i = 0; i < 20; i++ )
            {
                string Output;

                Output = "Student " + ( i + 1 ) + ": ";

                int ExamScoreSum = 0;

                for ( int j = 0; j < 4; j++ )
                {
                    Output = Output + StudentScores[i, j] + "; ";

                    ExamScoreSum += StudentScores[i, j];

                    switch ( j )
                    {
                        case 0:
                            Exam1Sum += StudentScores[i, j];
                            break;
                        case 1:
                            Exam2Sum += StudentScores[i, j];
                            break;
                        case 2:
                            Exam3Sum += StudentScores[i, j];
                            break;
                        case 3:
                            Exam3Sum += StudentScores[i, j];
                            break;
                        default:
                            break;
                    }
                }

                Output = Output + ( ExamScoreSum / 4 );

                Console.WriteLine( Output );
            }

            int Exam1Avg = Exam1Sum / 4;
            int Exam2Avg = Exam2Sum / 4;
            int Exam3Avg = Exam3Sum / 4;
            int Exam4Avg = Exam4Sum / 4;
            int TotalAvg = ( Exam1Sum + Exam2Sum + Exam3Sum + Exam4Sum ) / 4;

            Console.WriteLine( "\nExam 1 Overall Average: {0}", Exam1Avg );
            Console.WriteLine( "Exam 2 Overall Average: {0}", Exam2Avg );
            Console.WriteLine( "Exam 3 Overall Average: {0}", Exam3Avg );
            Console.WriteLine( "Exam 4 Overall Average: {0}", Exam4Avg );
            Console.WriteLine( "All Exams Overall Average: {0}", TotalAvg );     

            Console.ReadKey( true );

        }
    }
}