4.1.24. Incorrect summary

  • T1


  • read_item(X);
  • X=X-N;
  • write_item(X);


  • read_item(Y);
  • Y=Y-N;
  • write_item(Y);
  • T2
  • sum=0;
  • read_item(A)
  • sum=sum+A;


  • read_item(X);
  • sum=sum+X;
  • read_item(Y);
  • sum=sum+Y;
  • T2 sums after X-N and before Y-N