Thread: Segmentation Fault :(

Code:

    //creates customer of the struct rider;
    rider customer;

    //while the infile can be read from
    while(inFile)
    {

    //it will loop and read from the inFile data while the customer data
    //is not equal to END 0 0 
    while(!(customer.lastName == "END" && customer.tickets == 0 && customer.time ==0))
    {

you havent done anything with 'customer' so why compare its fields? lastName will be empty string (i think) and the two ints will be undefined (likely some random number left over from the memory at that address). this code runs, however there is obviously some logic error. maybe you want a do-while loop? you may need to look over your other loops and consider a do-while loop instead.

edit: also instead of while(inFile) use while(inFile.good())

the program still never exists for me. im saying that first do loop is fine (at least the one i tried, as i posted above).

look over the logic of your other loops.. others may need to be changed to do...while loops, maybe not though havent looked them over. also be careful with all of your conditions and using !not, is there a logic error there? must be somewhere down there.

the inifinite loop occurs within this while loop:

Code:

while(!(arrivals.empty() == true && line.empty() == true && backIn.empty() == true))

most likely meaning the condition your checking here isnt right.. is it?

If you also post the example input file which makes it crash for you, then we'd be able to replicate what you're doing.

example input file was posted little while ago, name it 'riders.dat'

Hopper 2 1 Torvalds 3 10 Jobs 8 4 Gates 100 100 END 0 0

is there ever a time where that while loop will be false? let me try and rewrite it

while(!(arrivals.empty() == true && line.empty() == true && backIn.empty() == true))
the above is _always_ true, so:

while(arrivals.empty() == true && line.empty() == true && backIn.empty() == true)
the above is _always_ false, so, removing the '== true', we have:

while(arrivals.empty() && line.empty() && backIn.empty())
the above is _always_ false

therefore all 3 of these will never be empty at the same time.. either your checking the wrong condition, or you have some logic error somewhere that is preventing this condition from being true.

your code is somewhat difficult to follow, which is making this difficult to debug.. i would have to print your code and sit down and try and understand it, or read the assignment sheet (if any) to understand what you are _trying_ to do.

i just want it to loop through while all of the queues still have stuff in them, thats now what that first statement says? I mean how else would i have the loops set up to do what i want? i can't think of a way.

it does say that.

your original condition:

Code:

while(!(arrivals.empty() == true && line.empty() == true && backIn.empty() == true))

(in your code/logic) this condition is always true.

the above is the same as saying:

Code:

while(!(arrivals.empty() && line.empty() && backIn.empty()))

which is the same as saying:

Code:

while(!arrivals.empty() && !line.empty() && !backIn.empty())

again, this is always true.

what this means is that there is never a time in your code that will make this condition false. arrivals, line, and backin will never be empty.

again, your while loop does say what you want it to, however, it results in an infinite loop. so the condition is never false, so its some logic your doing within this while loop.. somewhere in all those ifs and pops and pushes, which i wont go through and figure out what your supposed to be doing.

re-read your assignment sheet or whatever this is for/from to see what your supposed to do there.

Um, nadroj, I think you did not get your De Morgan's theorem correct.

Code:

while(!(arrivals.empty() == true && line.empty() == true && backIn.empty() == true))

is indeed equivalent to

Code:

while(!(arrivals.empty() && line.empty() && backIn.empty()))

But now the above is equivalent to:

Code:

while(!arrivals.empty() || !line.empty()|| !backIn.empty())