Condition operators don't give correct result - ruby

Question

I am trying to develop a battleship game in console. I need input of coordinates that guess where the game is. I did it:
#array1 and array2 are not obvious boards of player1 and player2 respectly
array1 = [ ['*', 'A', 'B', 'C', 'D', 'E'],['1',0, 1, 1, 1, 0], ['2',1, 0, 0, 0, 0], ['3',1, 0, 1, 0, 0], ['4',0, 0, 1, 0, 1], ['5',0, 0, 0, 0, 0] ]
array2 = [ ['*', 'A', 'B', 'C', 'D', 'E'],['1',1, 0, 1, 1, 0], ['2',0, 0, 0, 0, 1], ['3',0, 1, 0, 0, 1], ['4',0, 1, 0, 0, 1], ['5',0, 0, 0, 0, 0] ]
#arr1 and arr2 are obvious boards of player1 and player2 respectly
arr1 = [['*', 'A', 'B', 'C', 'D', 'E'],['1','.','.','.','.','.'],['2','.','.','.','.','.'],['3','.','.','.','.','.'],['4','.','.','.','.','.'],['5','.','.','.','.','.']]
arr2 = [['*', 'A', 'B', 'C', 'D', 'E'],['1', '.','.','.','.','.'],['2', '.','.','.','.','.'],['3', '.','.','.','.','.'],['4', '.','.','.','.','.'],['5', '.','.','.','.','.']]
coor = ['A', 'B', 'C', 'D', 'E']
#board1 and board2 are the final boards of player1 and player2
#this arrays will be seen during game
#every changes will be seen on these boards
board1 = arr1.map { |x| x.join(' ') }
board2 = arr2.map { |x| x.join(' ') }
#num1 and num2 are the numbers of the parts of ships respectively
num1 = 8
num2 = 8
#count1 and count2 are the numbers of poped ship parts respectively
count1 = 0
count2 = 0
#Starting of the game and the printing the board
#If we type "start" game will be started
#"Reset" game will be ended
#If we type words except "start" or "reset" program will ask "Do you want to start? (start/reset)" again
while true do
puts "Welcome to the game!!!"
puts "Do you want to start? (start/reset):"
respond = gets.chomp
if respond == 'start'
puts "\n"
puts "Player ONE"
puts board1
puts "\n"
puts "Player TWO"
puts board2
while true do
#Burada while ile player1 in shertleri olacaq
while true do
puts "\n"
puts "Turn - Player ONE"
puts "Enter coordinate: "
a = gets.chomp
a1 = a.split('')
b = coor.index(a1[0]) +1
col1 = b
row1= a1[1].to_i
if a == '""'
puts "You have to enter any coordinate"
break
elsif array1[row1][col1] == 'X' or array1[row1][col1] == '0'
puts "You have already bumped this coordinate!"
elsif col1<1 or col1>5 or row1>5 or row1<1
puts "This coordinate is out of board"
else
if array1[row1][col1] == 1
count1 = count1 + 1
arr1[row1][col1] = "X"
elsif array1[row1][col1] == 0
arr1[row1][col1] = "0"
end
board1 = arr1.map { |x| x.join(' ') }
puts "\n"
puts "Player ONE"
puts board1
puts "\n"
puts "Player TWO"
puts board2
if count1 == num1
puts "Player ONE won the game!"
break
end
end
break
end
while true do
#Burada while ile player2 in shertleri olacaq
puts "\n"
puts "Turn - Player TWO"
puts "Enter coordinate: "
c = gets.chomp
c1 = c.split('')
d = coor.index(c1[0]) + 1
col2 = d
row2= c1[1].to_i
if c == '""'
puts "You have to enter any coordinate"
break
elsif array2[row2][col2] == 'X' or array2[row2][col2] == '0'
puts "You have already bumped this coordinate!"
elsif col2<1 or col2>5 or row2>5 or row2<1
puts "This coordinate is out of board"
else
if array2[row2][col2] == 1
count2 = count2 + 1
arr2[row2][col2] = "X"
elsif array2[row2][col2] == 0
arr2[row2][col2] = "0"
end
board2 = arr2.map { |x| x.join(' ') }
puts "Player ONE"
puts board1
puts "\n"
puts "Player TWO"
puts board2
if count2 == num2
puts "Player TWO won the game!"
break
end
end
break
end
end
elsif respond == 'reset'
puts "You are off the game"
break
else
puts "\n"
puts "Answer can be only {start} or {reset}"
end
end
There are some problems, and I added if elsif else conditions to the code to solve them. One of them is for entering coordinates out of board, the second one is for not entering any coordinate, and the last one is for bumped coordinate. If these three condition are bypassed, the players can enter any coordinate.
But these codes don't work. When I check these three conditions, the result is an error. Can anyone tell me what the problem is with these conditions? Why don't they give suitable result?

Answer 1

When entering A8 as a value, the error you get is:
battleship.rb:54:in `<main>': undefined method `[]' for nil:NilClass (NoMethodError)
This is line 54:
elsif array1[row1][col1] == 'X' or array1[row1][col1] == '0'
In this case, the error is that array1["8"] is nil, and nil["A"] is undefined. An easy fix is to move line 56 above this one (the one that checks whether the input is actually within the board range).
elsif col1<1 or col1>5 or row1>5 or row1<1
If you do that, then since 8 is greater than 5, you'll get the "out of board" message rather than an error.
The other error you mention is when you put in an empty string. In that case the error is:
battleship.rb:48:in `<main>': undefined method `+' for nil:NilClass (NoMethodError)
Line 48 says:
b = coor.index(a1[0]) +1
In this case, the index is returning nil, and you can't add 1 to nil.
One way to fix this is to move the section a few lines down that checks whether a is blank to before line 48.