# Grades1 Example
# Source code file: grades1.py
# Input file: grades.txt

# Compute the sum of all the grades.
# Important: don't forget the second
# readline statement at the end of the
# while loop.  Without it, the while
# loop is an infinite loop.

sum = 0
fin = open("grades.txt", "r")

# Read first line from file
line = fin.readline( )

# Process lines until end of file
while line != "":
    grade = int(line.strip( ))
    sum = sum + grade
    line = fin.readline( )

print("Sum of grades:", sum)
fin.close( )

# Output:
# Sum of grades: 711