If you try to run the fllowing program,how long would it take?

c=clock
d=c(3)
while d==c(3)
c=clock;
end

what's the meaning of"if you insist on running it,change both 3's to 5's "?

this code is copy from P44, Experiments with MATLAB,Cleve Moler

Answer 1

[Star Strider]

My guess would be until local midnight the day the program started.

[marina]

why?

[Star Strider]

Because if you do:

c = clock

the result (just now, GMT-6) is:

c =

           2014       7        1       21        22      22.94

The third element is the day ( 1 here ), so since the loop continuously polls the clock function, that element will change to 2 at local midnight, d will no longer equal c(3) and the loop will stop.

If you change the 3’s to 5’s, the element changes to the minute element, and the program will run for at most one minute and then stop.

[marina]

thanks！：）