How to convert script from fortran90 to matlab language

Can anyone help me to covert this script

Thank you

DIMENSION KB(10) KA(10)   

KL=0
      KS=1
      DO 210 K=1,N0
      K1=K+1
      IF(A(K)*A(K1).LT.0.)THEN
      KS=-KS
      IF(KS.EQ.-1)THEN
      KL=KL+1
      KA(KL)=K1
      ENDIF
      IF(KS.EQ.1)THEN
      KB(KL)=K
      ENDIF
      ENDIF
210   CONTINUE
      IF(KL.GT.0)THEN
      DO 230 KQ=1,KL
      KAL=KA(KL)
      KBL=KB(KL)
      K0=KAL-1
      K1=KBL+1
      XA=H*FLOAT(K0)
      XB=H*FLOAT(K1)
      FA=A(K0)
      FB=A(K1)
      DO 220 K=KAL,KBL
      XK=H*FLOAT(K)
      A(K)=FA+(FB-FA)*(XK-XA)/(XB-XA)
220   CONTINUE
230   CONTINUE
      ENDIF

[Fabio Freschi]

this is not a complete Fortran script (and it doesn't use F90 syntax): some variable are missing, such as N0,

Answer 1

[Fabio Freschi]

Again, it is difficult to check if not all code is available, however I try

kB = zeros(10,1);
kA = zeros(10,1);
kL = 0;
kS = 1;

for k = 1:N0
    k1 = k+1;
    if A(k)*A(k1) < 0
        kS = -kS;
        if kS == -1
            kL = kL+1;
            kA(kL) = k1;
        end
        if kS == 1
            kB(kL) = k;
        end
    end
end
        
if kL > 0 
   for kQ = 1:kL
       kAL = kA(kL);
       kBL = kB(kL);
       k0 = kAL-1;
       K1 = kBL+1;
       xA = H*double(k0);
       xB = H*double(k1);
       FA = A(k0);
       FB = A(k1);
       for k = kAL:kBL
           xK = H*double(k);
           A(k) = FA+(FB-FA)*(xK-xA)/(xB-xA);
       end
   end
end

It goes without saying that this is an attempt to translate the code line-by-line, but it could not be the best matlab code.

[m m]

Dear Fabio Freschi Thank you very much, please can you translate this two statements to Matlab language :

  REAL A(0:N)
  REAL B(N)

[Fabio Freschi]

They are declaration of variables.

The second is simple, just allocate the memory for a double array

b = zeros(N,1);

The first is similar. The only problem is that the variable is declared assuming 0-indexing. Matlab does not allow 0-indexing so you can write

a = zeros(n+1,1);

and scale the 1-indexing in the code

[m m]

Thank you Sir,