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Another make task, and this time the program has to read a whole file without knowing how long it is.

A teacher has a text file called test_scores.txt containing the exam results for a class. Every student’s score is on a line of its own, but the teacher does not know exactly how many students are in the file. It might look like this:

Your task

Write a program that uses a condition controlled loop to read through the entire file and count how many students achieved a passing score: 50 or more.

The program should:

open the text file test_scores.txt in read mode,
create a counter variable starting at 0 to track the number of passes,
read the first line of the file,
use a while loop that keeps going as long as the line it read is not an empty string (""),
inside the loop, convert the current line to an integer,
check whether that score is greater than or equal to 50,
add 1 to the pass counter if it is,
read the next line of the file before the loop starts again,
close the file once the loop has finished,
output the final pass count.

The program asks the user nothing: everything it needs is in the file.

The tests also check your code: use a while loop to read the file.

The output

One line, where N is the number of scores of 50 or more:

Number of students who passed: N

Testing

Each test puts a different test_scores.txt next to your program before it runs, and the name of each test says what that file held. The files have different lengths, from a whole class down to a single student, and one of them is empty. An empty file has no scores in it, so nobody passed.

Example

With the seven scores shown above in test_scores.txt:

Output:

Number of students who passed: 4

72, 50, 91 and 63 are passes. 50 counts, since it is exactly the pass mark; 49 does not.

To try your program before you submit it, use the To sandbox button at the bottom of the editor. The sandbox comes with the test_scores.txt shown above.

Help! My code doesn't work!

Make sure that you check for the following things:

The pass counter is created before the loop and given the value 0.
There is one .readline() before the loop and one at the end of the loop’s body. Without the second one the loop never ends.
The condition is line != "", with nothing at all between the two quotes.
Each line is wrapped in int() before it is compared with 50.
The comparison is >= 50, so that a score of exactly 50 is a pass.
The file is closed and the count printed after the loop, not indented.
The pass count is wrapped in str() before it is joined onto the message.