TI-BASIC:Connect 4 2 Player

This is your Basic connect 4 game. Drop Checkers down any of the 7 columns, taking turns until either the board is filled of one player gets four in a row. Try to understand the code. It uses Matrix [A] to track the game board, Var P as one or two to track whose turn it is, V as the input-ed column, L2 as the height of the columns, And Z as the counter for the possible number of turns.

The Code

DelVar [A]:{6,7->dim([A]            //sets [A] to 6x7 all 0's
Disp"
Disp"+-+-+-+-+-+-+-+
For(A,1,5
Disp"]
End
Output(8,1,"]
For(A,3,8
Output(A,15,"[
End
For(A,1,8
Output(A,16,sub("PLAYER_ _",A,1                                            //"_" is a space
End
0->θ
2->P
{6,6,6,6,6,6,6->L2:0->θ
For(Z,1,42
If θ
Goto 1
(P=1)2+(P=2)->P
Output(8,16,P
2->V
Repeat K=105 and L2(V/2
Output(1,V,"v
Repeat K
getKey->K
End
Output(1,V,"_
V+2(K=26 and V<=12)-2(K=24 and V>=4)->V
End
V/2->V
P(P=1)+(P-3)(P=2)->[A](L2(V),V)
If P=1
Output(2+L2(V),2V,"0                                           //zero
If P=2
Output(2+L2(V),2V,"O                                          //letter O
0->θ
If L2(V)<=3
Then
For(A,7,5,-1
cumSum(seq([A](A-I,V),I,1,4
If Ans(4)=4
1->θ
If Ans(4)=-4
-1->θ
End
End
For(A,0,3
cumSum(seq([A](L2(V),A+I),I,1,4
If Ans(4)=4
1->θ
If Ans(4)=-4
-1->θ
End
V+L2(V->B
If B>=5 and B<=10
Then
seq([A](1,B-I),I,(B<=7)(B-1)+6(B>=8),(B<=7)+(B>=8)(B-7),-1->L1
For(A,1,dim(L1)-3
cumSum(seq(L1(M),M,A,A+3
If Ans(4)=4
1->θ
If Ans(4)=-4
-1->θ
End
End
L2(V)-V->B
If B<=2 and B>=-3
Then
seq([A](I,I-B),I,(B<=-1)+(B+1)(B>=0),6(B>=0)+(B+7)(B<=-1)->L1
For(A,1,dim(L1)-3
cumSum(seq(L1(M),M,A,A+3
If Ans(4)=4
1->θ
If Ans(4)=-4
-1->θ
End
End
L2(V)-1->L2(V
End
Lbl 1
ClrHome
"PLAYER_
If θ=1
Ans+"1
If θ=~1
Ans+"2
Ans+" WINS!
If Z=42
"CAT GOT THE GAME
Ans

Credits

This Game was coded by TI-GBR and optimised by jonbush and earthnite. See development page