...

function [Cv,Cm,Ctheta,Cdelta]= ...
  constant(M1,M2,Blen,S_type, ...
           Vl,Ml,Thetal,Deltal);
%
% [Cv,Cm,Ctheta,Cdelta]= ...
%   constant(M1,M2,Blen,S_type, ...
%            Vl,Ml,Thetal,Deltal);
% ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
% This function determines the constants
% of integration for the beam.
%
% M1     - applied moment at left boundary
% M2     - applied moment at right boundary
% Blen   - length of beam
% S_type - type of support system
%          =1, pin-pin
%          =2, fixed-fixed
% Vl     - shear value for discontinuity
%          function evaluated at x=Blen
% Ml     - moment value for discontinuity
%          function evaluated at x=Blen
% Thetal - rotation value for discontinuity
%          function evaluated at x=Blen
% Deltal - deflection value for discontinuity
%          function evaluated at x=Blen
% 
% Cv     - shear constant of integration
% Cm     - moment constant of integration
% Ctheta - rotation constant of integration
% Cdelta - deflection constant of integration
%
% User m functions called:  none.
%----------------------------------------------

if S_type == 1
  %...pin-pin
  Cv=(M2-M1-Ml)/Blen; Cm=M1; Cdelta=0;
  Ctheta=-(Deltal+Cv*Blen^3/6+ ...
         Cm*Blen^2/2)/Blen;
elseif S_type == 2
  %...fixed-fixed
  Ctheta=0; Cdelta=0;
  a=[Blen^2/2  Blen    ; ...
     Blen^3/6  Blen^2/2];
  b=[-Thetal;  -Deltal];
  x=a\b; Cv=x(1); Cm=x(2);
end