if(check) command in Matlab

Question

I recently saw this function in a program I am studying. The global, check is set to equal one:

s=snew(s_old, beta,alpha,dt)
global check
s=s_old+dt*alpha/(1+dt*alpha*beta);
if(check)
   chsnew=(s-s_old)/dt-(s-(alpha-(1-s)-beta*s);
end

I don't understand the if(check) sequence. Can someone explain?

Answer 1

The global variable "check" can be set to 1 or 0 in order to enter or not in the "if" statement.

The same can be done for example when you are debugging code and want to execute some instructions in this context:

debug=1;
if (debug)
   <code to execute when debugging>
end