C++ Output Problem

Assmaster_Kronk

Hi i'm trying to output a series of strings to one line in a text file, but i'm getting a weird problem where the last three values entered duplicate themselves, ignore the spaces, and become fragmented, code below:

ReservationInput << Customer.Cust_Name
<< " " << Customer.Cust_Address
<< " " << Customer.Cust_CredNo
<< " " << Customer.CardExp_Date
<< " " << Customer.Card_Company
<< " " << Customer.Card_Status << endl;

Output:

JimBob 25NortStreet 12345678912909MA 2909MA MA A


Any help much appreciated:)

Webmonkey

did you try couting it to the screen and see if you get similar result

Assmaster_Kronk

Yep, outputs exactly the same when printed to screen

ron_darrell

A cout is a cout - it will only print what you've asked it to. I doubt the problem is with this part of your code. More likely it's with the part that assigns the various values to the various variables. Recheck where the assignment happens. It could be a memory out-of-bounds for the string is causing the other values to be overwritten - a string in c++ is basically a character array. If you tell the array to expect 10 chars but you feed it 16 then it will do as it's told and fill the 10 then borrow the space for the last 6 from someplace else (and usually close by - say the space normally used for the two variables after?)

-RD

Assmaster_Kronk

ron_darrell wrote: »

A cout is a cout - it will only print what you've asked it to. I doubt the problem is with this part of your code. More likely it's with the part that assigns the various values to the various variables. Recheck where the assignment happens. It could be a memory out-of-bounds for the string is causing the other values to be overwritten - a string in c++ is basically a character array. If you tell the array to expect 10 chars but you feed it 16 then it will do as it's told and fill the 10 then borrow the space for the last 6 from someplace else (and usually close by - say the space normally used for the two variables after?)

-RD

Yeah i double checked the inputs and made the character arrays bigger then they needed to be just to check if anything was overlapping, printing each value separately after the input showed no problems whatsoever, its only when i write it to a file or the screen i get irregularities

Assmaster_Kronk

Solved the problem, i just got rid of the structure and had each variable as just normal strings, no idea why it was a problem in the first place though:p

Creamy Goodness

why is the customer a structure?

surely it should be a class as you're using C++?

have all the relevant data as private data memebers of the customer class and write getter functions to access the variables.

for example.

customer cust1 = new customer("JimBob", "25NortStreet", "12345678912909MA", "2909MA", "MA", "A");

/*example print out.*/
cout << cust1.getName() << endl;

that being said there's nothing wrong with structures, but i'm only guessing that this is a college assignment for a certain lecturer that i know well and that lecturer will be looking for objects instead of structures.

SirLemonhead

Assmaster_Kronk wrote: »

Yeah i double checked the inputs and made the character arrays bigger then they needed to be just to check if anything was overlapping, printing each value separately after the input showed no problems whatsoever, its only when i write it to a file or the screen i get irregularities

Why are you not using std::string?

SonOfPerdition

Creamy Goodness wrote: »

why is the customer a structure?

surely it should be a class as you're using C++?

have all the relevant data as private data memebers of the customer class and write getter functions to access the variables.

for example.

customer cust1 = new customer("JimBob", "25NortStreet", "12345678912909MA", "2909MA", "MA", "A");

/*example print out.*/
cout << cust1.getName() << endl;

that being said there's nothing wrong with structures, but i'm only guessing that this is a college assignment for a certain lecturer that i know well and that lecturer will be looking for objects instead of structures.

of course there is nothing wrong with using structures.

By definition, a struct is a class in which members are by default public; that is, struct s{ is simply shorthand for class s{public

Bjarne Stroustrup

DaSilva

Assmaster_Kronk wrote: »

Solved the problem, i just got rid of the structure and had each variable as just normal strings, no idea why it was a problem in the first place though:p

This is just a guess since I can't see the rest of the code, but is it possible some of those strings were not NULL terminated?

JimBob 25NortStreet 12345678912909MA  2909MA  MA  A

is what you got, and I think you were expecting:

JimBob 25NortStreet 123456789 12909  M  A

Since Cust_CredNo and the other remaining strings all print all the way to the "A", im guessing none of these strings are NULL terminated except "A", and they are located directly after each other in memory. Therefore cout is just printing from the first character of CredNo until it reaches a NULL which isn't until the Card_Status array.