function?[sysx0strts]?=?sfuntemp（txuflag）

g=10;
L=1;
switch?flag
??case?0
????[sysx0strts]=mdlInitializeSizes;
??case?1
????sys=mdlDerivatives（txugL）;
??case?2
????sys=mdlUpdate（txu）;
??case?3
????sys=mdlOutputs（txu）;
??case?4
????sys=mdlGetTimeOfNextVarHit（txu）;
??case?9
????sys=mdlTerminate（txu）;
??otherwise
????DAStudio.error（‘Simulink:blocks:unhandledFlag‘?num2str（flag））;
end

function?[sysx0strts]?=?mdlInitializeSizes

sizes?=?simsizes;
sizes.NumContStates??=?2;
siz