MATLAB: Someone correct me please! How can i plot with this codes to get the following graph

double U(N*2+2),A(N*2+2),B(N*2+2),C(N*2+2),D(N*2+2),Y(N*2+2);
double onesN=1.0/(double)N;
double Re=5000;
double EE=1.0;
double t=0;
double dt=EE*Re*N^2;
double AA=-0.5*EE;
double BB=1.0+EE;
KKEND=12;
KKMOD=1;
double Y(1)=0;
U(1)=0.0;
U(x)=1.0;
N=20
for j=2:N;
    U(j)=0.0;
    A(1),B(1),C(1),D(1)=1.0;
end
for j=2:N;
    Y(j)=Y(j-1)+N;
    A(j)=AA;
    if j==N
        A(j)=0.0;
        D(j)=BB;
        B(j)=AA;
    end
    if j==2
        B(j)=0.0;
        C(j)=1.0-EE*U(j)+0.5*EE*U(j+1)+U(j-1);
    end
    if j==N
       C(j)=C(j)-AA*U(x);
    end
end
for j=3:N;
    D(j)=D(j)-B(j)*A(j-1)/D(j-1);
    C(j)=C(j)-C(j-1)*B(j)/D(j-1);
    for k=2:N;
        M=N-(k-2);
        U(M)=(C(M)-A(M)*U(M+1))/D(M);
        Y(1)=0.0;
        Y(x)=Y(N)+N;
        t=t+dt;
    end
end

Best Answer

Here's a start, but what is N and x? And you didn't call plot(), so what, in this alphabet soup of a program, is being plotted along the x and y axes?
N = 100;  % Just a guess!!!
U = zeros(N*2+2);
A = zeros(N*2+2);
B = zeros(N*2+2);
C = zeros(N*2+2);
D = zeros(N*2+2);
Y = zeros(N*2+2);
onesN=1.0/N;
Re=5000;
EE=1.0;
t=0;
dt=EE*Re*N^2;
AA = -0.5 * EE;
BB = 1.0 + EE;
KKEND=12;
KKMOD=1;
Y(1)=0;
U(1)=0.0;
U(x)=1.0;
N=20
for j=2:N
  U(j)=0.0;
  A(1) = 1.0;
  B(1) = 1.0;
  C(1) = 1.0;
  D(1) = 1.0;
end
for j=2:N
  Y(j)=Y(j-1)+N;
  A(j)=AA;
  if j==N
    A(j)=0.0;
    D(j)=BB;
    B(j)=AA;
  end
  if j==2
    B(j)=0.0;
    C(j)=1.0-EE*U(j)+0.5*EE*U(j+1)+U(j-1);
  end
  if j==N
    C(j)=C(j)-AA*U(x);
  end
end
for j=3:N
  D(j)=D(j)-B(j)*A(j-1)/D(j-1);
  C(j)=C(j)-C(j-1)*B(j)/D(j-1);
  for k=2:N
    M=N-(k-2);
    U(M)=(C(M)-A(M)*U(M+1))/D(M);
    Y(1)=0.0;
    Y(x)=Y(N)+N;
    t=t+dt;
  end
end
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