> For the complete documentation index, see [llms.txt](https://www.csprinciples.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.csprinciples.com/25-26/session-18.md).

# Session 18

## Source Code

```lua
local myName = ""
print("Name: " .. myName)

-- define main function
function main()
    print("Hello Main Function")
    print(myName)
    local choice = nil
    print("Menu")
    print("E1 - Example 1")
    print("Q - Quit")
    io.write("Choice: ")
    choice = io.read()
    if choice == "E1" then
        -- Example 1 Function call
        example1()

    elseif choice == "E2" then
        -- Example 2 Function call
        example2()

    elseif choice == "E3" then
        -- Example 3 Function call
        example3()

    elseif choice == "E4" then
        -- Example 4 Function call
        example4()

    elseif choice == "Q" then
        done = true
    else
        print("Invalid Choice")
    end
end

-- define Example 1 Function
function example1()
    print("Example 1")
    -- define friends list
    

    -- print the number of elements
   

    -- print the element one by one
    

    -- using a for loop, print the index and elements
    

    -- assign value to first friend
    

    -- assign value to the last friend
    

    -- print the friends
    

end

-- define Example 2 Function
function example2()
    -- create an empty list
    

    -- add an element to the end of the list (append)
    

    -- add an element to the end of the list (append)
    

    -- add an element to the beginning of the list (insert)
    

    -- print using for in loop
    

    -- print using for in loop with index
    

    -- delete a fruit
    

    -- print using for in loop
    

end

-- define Example 3 Function
function example3()
    
end

-- define Example 4 Function
function example4()
    
end

-- call to main function, do not delete!
main()
```

## s18problem1.lua

```lua
-- function definition
function problem1()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()

```

## s18problem2.lua

```lua
-- function definition
function problem2()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()

```

## s18problem3.lua

```lua
-- function definition
function problem3()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()

```

## s18problem4.lua

```lua
-- function definition
function problem4()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()

```

## s18problem5.lua

```lua
-- function definition
function problem5()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()

```

## s18problem6.lua

```lua
-- function definition
function problem6()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()

```

## s18problem7.lua

```lua
-- function definition
function problem7()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()
```

## s18problem8.lua

```lua
-- function definition
function problem8()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()
```

## s18problem9.lua

```lua
-- function definition
function problem9()

end

-- function definition
function main()
    -- function call

end

-- call to main function
main()
```

## playlist.lua

```lua
-- main function
function main()
    -- Initialize playlist with 10 songs
    local playlist = {}

    local done = false
    while not done do
        print("My Playlist Manager")
        print("1. View playlist")
        print("2. View playlist with index positions")
        print("3. Add a song")
        print("4. Remove a song")
        print("5. Select a random song")
        print("6. Sort playlist")
        print("7. Shuffle playlist")
        print("8. Reorder playlist")
        print("9. Clear playlist")
        print("10. Exit")
        io.write("Choose an option (1-10): ")
        local choice = io.read("*n")
        io.read()
        if choice == 1 then
            print("My current playlist")


        elseif choice == 2 then
            print("My current playlist with index positions")
            
            
        elseif choice == 3 then
           print("Add a song")


        elseif choice == 4 then
            print("Remove a song")


        elseif choice == 5 then
            print("Here's a random song!")
            

        elseif choice == 6 then
            print("Sort my playlist alphabetically")
            
            
        elseif choice == 7 then
            print("Shuffle playlist")
            -- Loop through the list from the last index to the second index. 

                -- Generate a random index between 1 and i
                
                -- Swap elements at index i and j
                


        elseif choice == 8 then
            print("Reorder playlist")
            

        elseif choice == 9 then
            print("Playlist cleared.")
            

        elseif choice == 10 then
            print("Goodbye!")
            done = true
        else
            print("Invalid choice. Please try again.")
        end
    end
end

-- Call the main function
main()
```


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