code review tutorial

main branch for code review tutorial:
3 text exercies
2 python excercises
2 Fortran excercies

issues/ contains the .md files used in the issue bodies
pull_requests/ contains the .md file used in the pull request bodies

workflows - run on demand
  create_exercises - opens the issues and linked pull requests for
                     selected language
  close_issues_and_pulls - closes all open issues and pull requests

.github/workflows/close_issues_and_pulls.yaml

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+name: reset_exercises
+on: 
+  workflow_dispatch:
+permissions: write-all
+jobs:
+  close-pulls:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    steps:
+      - uses: actions/checkout@v3
+      - run: | 
+          for p in $(gh pr list --json number --jq '.[].number'); do
+            gh pr close $p
+          done
+  close-issues:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    steps:
+    - uses: actions/checkout@v3
+    - run: | 
+        for p in $(gh issue list --limit 200 --json number --jq '.[].number'); do
+          gh issue close $p
+        done
+
+
+

.github/workflows/create_exercises.yaml

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+name: create_exercises
+on: 
+  workflow_dispatch:
+   inputs: 
+      language:
+        description: 'Language'
+        required: true
+        default: text
+        type: choice
+        options:
+        - text 
+        - python
+        - Fortran
+permissions: write-all
+jobs:
+  create-labels:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    steps:
+     - uses: actions/checkout@v3
+     - run: gh label create ${{ inputs.language }} -f
+  create-pulls-matrix:
+    needs: create-labels
+    strategy:
+      matrix:
+        exercise: [1, 2, 3]
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+    steps:
+      - run: |
+          echo "Language: ${{ inputs.language }}"
+          echo "Exercise: ${{ matrix.exercise }}"
+      # checkout repo
+      - uses: actions/checkout@v3
+        with: 
+         fetch-depth: 0
+      - name: create issue for exercise ${{ inputs.exercise }}
+        # check if the issue file exists before creating the issue
+        # store created issue in BAR to use in pull request text
+        env:
+          issueFile: 'issues/${{ inputs.language }}-ex${{ matrix.exercise }}-issue.md'
+        if: hashFiles(env.issueFile) !='' 
+        run: |
+          echo "BAR=$(gh issue create --title "${{ inputs.language }}: Exercise ${{ matrix.exercise }}" --body-file "issues/${{ inputs.language }}-ex${{ matrix.exercise }}-issue.md" --label ${{ inputs.language }})" >> $GITHUB_ENV
+      - name: query_branch_exists
+        run: |
+          echo "FOO=$(git branch -r | grep "${{ inputs.language }}-${{ matrix.exercise }}")" >> $GITHUB_ENV
+      - name: create pull request for exercise ${{ matrix.exercise }}
+        run: | 
+          if [ '${{ env.FOO }}' == '' ]; then
+            echo "no branch ${{ inputs.language }}-${{ matrix.exercise }} to create pull request from"
+          else
+             cat pull_requests/${{ inputs.language }}-ex${{ matrix.exercise }}-pullbody.md > pullbody
+             echo "Fixes ${{ env.BAR }} ${{ inputs.language }}" >> pullbody
+             gh pr create -B main -H "${{ inputs.language }}-${{ matrix.exercise }}" --title 'Exercise ${{ matrix.exercise }} ${{ inputs.language }}.' --body-file pullbody --label ${{ inputs.language }}
+          fi 

.gitignore

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+a.out
+*.o
+*.mod
+*.exe
+__pycache__/

Fortran/exercise1/Makefile

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+FC=gfortran #fortran compiler
+FFLAGS=-O2
+SRC=calc_pi.f90
+OBJ=${SRC:.f90=.o} #substitute .f90 with .o
+
+%.o: %.f90 #wildcard rule, creation of *.o depends on *.f90
+	$(FC) $(FFLAGS) -o $@ -c $<
+
+calc_pi.exe: $(OBJ)
+	$(FC) $(FFLAGS) -o $@ $(OBJ) 
+
+clean: #cleans all the old compilation files
+	@rm -f *.mod *.o *.exe

Fortran/exercise1/calc_pi.f90

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+program calc_pi
+implicit none
+
+integer, parameter :: num_samples = 1000000  ! Number of random samples
+
+real :: x, y
+real :: pi_approx
+integer :: i, count_inside_circle
+
+count_inside_circle = 0
+
+! Loop through random points and check if they fall inside the unit circle
+do i = 1, num_samples
+    call random_number(x)
+    call random_number(y)
+
+    if (x**2 + y**2 <= 1.0) then
+        count_inside_circle = count_inside_circle + 1
+    end if
+end do
+
+! Approximate pi value
+pi_approx = 4.0 * real(count_inside_circle) / real(num_samples)
+
+print *, "Approximated value of pi:", pi_approx
+
+end program calc_pi
+

Fortran/exercise2/Makefile

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+FC=gfortran #fortran compiler
+FFLAGS=-O2
+SRC=league_sim.f90
+OBJ=${SRC:.f90=.o} #substitute .f90 with .o
+
+%.o: %.f90 #wildcard rule, creation of *.o depends on *.f90
+	$(FC) $(FFLAGS) -o $@ -c $<
+
+league_sim.exe: $(OBJ)
+	$(FC) $(FFLAGS) -o $@ $(OBJ) 
+
+clean: #cleans all the old compilation files
+	@rm -f *.mod *.o *.exe

Fortran/exercise2/league_sim.f90

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+program football_league_simulator
+    implicit none
+
+    integer, parameter :: num_teams = 5
+    integer :: points(num_teams)
+    character(len=20) :: team_names(num_teams) = ['Team A', 'Team B', 'Team C', 'Team D', 'Team E']
+    integer :: i, j
+
+    ! Initialize points
+    points = 0
+    ! Simulate matches and update points
+    do i = 1, num_teams
+        do j = i+1, num_teams
+            call simulate_match(i, j, points)
+        end do
+    end do
+
+    call sort_teams(team_names, points)
+
+    ! Print results
+    call print_results(team_names, points)
+
+
+contains
+
+subroutine simulate_match(team1, team2, points)
+    implicit none
+    integer, intent(in) :: team1, team2
+    integer, intent(inout) :: points(:)
+
+    integer :: goals1, goals2
+    real :: g1, g2        
+
+    call random_seed()
+
+    ! Simulate goals for each team (max 5 goals)
+    call random_number(g1)
+    call random_number(g2)
+    goals1 = floor(6*g1) 
+    goals2 = floor(6*g2)
+
+    ! Update points based on match result
+    if (goals1 > goals2) then
+        points(team1) = points(team1) + 3   ! Team 1 wins
+    else if (goals2 > goals1) then
+        points(team2) = points(team2) + 3   ! Team 2 wins
+    else
+        points(team1) = points(team1) + 1   ! Draw, each team gets 1 point
+        points(team2) = points(team2) + 1
+    end if
+
+end subroutine simulate_match
+
+subroutine sort_teams(team_names, points)
+    implicit none
+    character(len=20), intent(inout) :: team_names(:)
+    integer, intent(inout) :: points(:)
+    integer :: i, j
+    integer :: tempPoints
+    character(len=20) :: tempName
+
+    do i = 1, size(team_names) - 1
+        do j = 1, size(team_names) - i
+            if (points(j) < points(j + 1)) then
+                ! Swap points
+                tempPoints = points(j)
+                points(j) = points(j + 1)
+                points(j + 1) = tempPoints
+
+                ! Swap team names accordingly
+                tempName = team_names(j)
+                team_names(j) = team_names(j + 1)
+                team_names(j + 1) = tempName
+            end if
+        end do
+    end do
+end subroutine sort_teams
+
+
+
+subroutine print_results(team_names, points)
+    implicit none
+    character(len=20), intent(in) :: team_names(:)
+    integer, intent(in) :: points(:)
+    integer :: i
+
+
+    print *, "Football League Results:"
+    print *, "------------------------"
+    do i = 1, size(team_names)
+        print *, team_names(i), ": ", points(i), " points"
+    end do
+end subroutine print_results
+
+end program football_league_simulator

README.md

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+# Welcome to code review tutorial GitHub repository
+
+Vist [code-review.org](https://code-review.org/) to learn more. 
+
+This work was supported by the Better Scientific Software Fellowship
+Program, funded by the Exascale Computing Project (17-SC-20-SC), a
+collaborative effort of the U.S. Department of Energy (DOE) Office of
+Science and the National Nuclear Security Administration; and by the
+National Science Foundation (NSF) under Grant No. 2154495.

issues/Fortran-ex1-issue.md

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+## Fortran Exercise 1: Calculating Pi
+
+A program to calculate pi is being used as a sample code to 
+compare how compiler options affect run time.
+
+However, the program is producing an incorrect value for pi.
+
+Take a look at the code.
+
+* Are there any errors that standout?
+* Is the code easy to understand?
+* What changes, if any, would you make to the code?
+
+
+Take a look at the pull request
+
+* Does the pull request address the issue?
+* Are there any unnecessary or incorrect changes?
+* Why did the author change the precision? Can you find the commit message with the reason?
+
+

issues/Fortran-ex2-issue.md

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+## Fortran Exercise 2: Refactoring 
+
+A team member (Betty) has been working on a project to simulate
+a football league over a season. Betty's code is all in one 
+program in a single file, league_sim.f90. However, Betty would now like to use
+the routines contained in the main program in several of their other programs.
+
+Betty created a module to enable the routines to be used by other programs and
+submitted their changes in a pull request. They'd like you to take a look at their code 
+and offer suggestions on how to improve it.
+
+Take a look at the pull request:
+
+* What would make the pull request easier to review?
+* What would improve the pull request? Add a comment.
+* Are the comments up to date, necessary, helpful? 
+* Would you remove some of these comments? Add suggestions for which comments to remove and/or change.
+* Which module variables and routines should be public? 
+* Add a suggestion for which variables/routines to make private to the module.
+* Have any bugs been introduced during the code refactoring?

issues/python-ex1-issue.md

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+## Python Exercise 1: Printing out vowels and consonants
+
+A python script `vowel_counter.py` is supposed to print out the number of vowels and consonants in a string.
+Several users have reported problems, and one user has put in a pull request to improve the script. 
+
+User reports:
+
+```
+Only vowels are getting printed out! This script is not working
+```
+
+```
+This script is printing the number of consonants.
+Why is `vowel_counter.py` even printing out the number of consonants?  
+```
+
+Take a look at the python script.  
+
+* Can you see any errors?
+* Do you need to run the script to test the behavior?
+
+
+Take a look at the pull request.
+
+* Does the pull request address the issue?
+* Are the comments up to date, necessary, helpful? Would you remove some of these comments? Add suggestions for which comments to remove and/or change.
+* Are there any bugs?
+* What would improve the pull request? Could you use list comprehension? Would you except the solution as it is now?

issues/python-ex2-issue.md

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+## Python Exercise 2: Calculating experiment time windows
+
+A lab group is using a python script to calculate the number of hour-long 
+experiments between an initial and final time. 
+
+Some background: The goal is to run the NSF NCAR space weather model 
+[TIEGCM](https://www.hao.ucar.edu/modeling/tgcm/tie.php) and stop every
+hour to update the model using observations.
+Each experiment uses observations from +/- 30 minutes from when the model
+is stopped. This +/- 30 minutes is known as the experiment window.
+
+The input to the python script is the intial time, the final time, and the
+delta (the duration of a single experiment). The script calculates the number
+of experiments needed, and for each experiment caclulates the start and stop 
+for both the model and the window.
+
+The issue: For one set of experiments, the delta was accidentally entered 
+as negative. The number of windows was calculated correctly, but the times 
+for each of the windows were incorrect.
+
+The lab group want to add some error checking to the python script to prevent
+this error happening again. 
+
+Take a look at the script:
+
+* Where would you put the error check?
+* Are there other error checks that you think should be included in the script?
+
+Take a look at the pull request:
+
+* Does the pull request address the issue?
+* Are there any unnecessary or incorrect changes?
+* What would make the pull request easier to review?
+* What would improve the pull request? Add a suggestion.