Sequential programming

Sequential programming

Sequential Program:

P;

Q;

R;

x = 1; // P

y = x + 1; // Q

x = y + 2; // R

For every possible execution (e) of this program, P must precede

Q and Q must precede R.

forall e: P Q R

The operator means precedes or happens before. P Q means that

P must begin before Q begins and further P must finish before Q finishes

ie. there is no overlap in the execution of the instructions making up P & Q.

If each component P & Q is made up of several instructions then:

forall e: p1 p2 ... pm q1 q2 ... qn

There is a total ordering of the instructions making up P & Q.

Example

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