# gradereport.py
#
# Extracts data from a text file containing student records and 
# produces a grade report.

# Use constants for the filenames.
INPUT_FILE = "coursegrades.txt"
OUTPUT_FILE = "gradereport.txt" 

  # Open the two files.
studentFile = file( INPUT_FILE, "r" )
reportFile = file( OUTPUT_FILE, "w" )

  # Extract the course name.
courseName = studentFile.readline();

  # Print the report header.
reportFile.write( "STUDENT REPORT\n" )
reportFile.write( courseName )
reportFile.write( "-" * 40 + "\n" )

  # Initialize the two running totals. 
gradeTotal = 0
numStudents = 0

  # Process each record in the grade file.
studentId = studentFile.readline()
while studentId != "" :         
   
     # Extract the other two parts of the record.
   studentName = studentFile.readline()
   studentGrade = float( studentFile.readline() )
   
     # Add this grade to the running total.
   gradeTotal += studentGrade
   numStudents += 1

     # Print the output for this student.
   output = "%4s  %-20s  %6.2f\n" % \
            ( studentId.rstrip(), 
              studentName.rstrip(), 
              studentGrade )
   reportFile.write( output )
      
     # Extract the next record.
   studentId = studentFile.readline()
   
 # Compute the average grade.
avgGrade = gradeTotal / float( numStudents )

 # Print the footer.
reportFile.write( "-" * 40 + "\n" )
reportFile.write( "%-26s  %6.2f\n" % ("Average Grade", avgGrade) )

 # Close the two files.
studentFile.close()
reportFile.close()