copy the string

[meenal]

Hi all

I am facing the problem of grabage value while copying the string as follows-

char strTemp[150]="";
if (cls.GetVerifySucValue()==0)
strcpy(strTemp,"#No Suction or Discharge valves were found matching your Pre-Selection options");

(Actually this is in the intemmedite DLL so that i can not debug it)

Thanks in advance
Meenal

[Savage]

Hi all

I am facing the problem of grabage value while copying the string as follows-

char strTemp[150]="";
if (cls.GetVerifySucValue()==0)
strcpy(strTemp,"#No Suction or Discharge valves were found matching your Pre-Selection options");

(Actually this is in the intemmedite DLL so that i can not debug it)

Thanks in advance
Meenal

This is not going to work.char strTemp[150]="",it is not correct.Instead use

char strTemp[150];
and then strTemp[0]='\0' where '\0' is null terminating character which terminate the string,this means that now this string is empty and ready to copy data into it correctly

Savage.

[AdrianH]

This is not going to work.char strTemp[150]="",it is not correct.Instead use

char strTemp[150];
and then strTemp[0]='\0' where '\0' is null terminating character which terminate the string,this means that now this string is empty and ready to copy data into it correctly

Savage.

Sorry to disagree Savage, but it is valid to do that.

The code has nothing wrong with it. The garbage value is coming from somewhere else. If strTemp is being returned, that would probably be the problem as strTemp is located on the stack and is indeterminate after returning from the call.

If strTemp is not being returned, then you will have to provide more information to help you debug the problem.


Adrian

[Savage]

Sorry to disagree Savage, but it is valid to do that.

The code has nothing wrong with it. The garbage value is coming from somewhere else. If strTemp is being returned, that would probably be the problem as strTemp is located on the stack and is indeterminate after returning from the call.

If strTemp is not being returned, then you will have to provide more information to help you debug the problem.


Adrian

U are right.The problem is not in that part and the code is correct.I made a big stupid error. :(

Thanks,for correction!

Savage

[AdrianH]

U are right.The problem is not in that part and the code is correct.I made a big stupid error. :(

Happens to the best of us. ;)


Adrian

[Savage]

Happens to the best of us. ;)


Adrian

Tnx! ;)

Savage

[arunmib]

Try doing a "memset" of strTemp, before copying the string....

[AdrianH]

Try doing a "memset" of strTemp, before copying the string....

What is your reasoning for suggesting that?


Adrian

[arunmib]

What is your reasoning for suggesting that?


Adrian

Nothing much, I think it's always a safe habit to clear the location (critical ones) before using it. If some other section of code is overwriting this location (strTemp), now that location will be giving errornous or not acceptable result which would help in locating where the real problem would be....

Or did I say something wrong, if so then can you correct me....

[AdrianH]

Nothing much, I think it's always a safe habit to clear the location (critical ones) before using it. If some other section of code is overwriting this location (strTemp), now that location will be giving errornous or not acceptable result which would help in locating where the real problem would be....

Or did I say something wrong, if so then can you correct me....

Not exactly wrong, just redundant. The OP stated this:

char strTemp[150]="";

which means that it is already initialised. Doing a memset (I'm assuming you mean to all 0s) would just do the same thing.

Initialisation is always a good habit arunmib, and I'm glad you do it. Stack (auto) variables however are better initialised using compiler based initialisation techniques instead of using functional ones because it can be faster (though not necessarily true, the optimiser may be able to do additional things more easily) and because using the initialisation at declaration idiom is (in my mind at least) safer as you are ensuring that the variable is always initialised right from the beginning.

I don’t subscribe to initialising only critical variables before using them idiom. IMHO, I feel all variables are fairly critical to the operation of the function, otherwise you really shouldn’t have them. I feel all variables should be initialised at declaration, and let the optimiser remove any redundant initialisations from there.

Keep up the good work arunmib,


Adrian

[weaknessforcats]

The code as written runs just fine. The error is elsewhere.

Check every location that uses strTemp and verify there are no errors.

[pravin78]

Hi, It's always good to initialize char array with memset to avoid any memory corruption further ..memset(nameofarray,'\0',sizeof(nameofarray)).

[weaknessforcats]

Hi, It's always good to initialize char array with memset to avoid any memory corruption further ..memset(nameofarray,'\0',sizeof(nameofarray)).

This does no good. There are no provisions to force you to stay within array bounds and a zero may not be the correct initial value.

If you are in C, and the char array is to contain a C-string , then only element 0 need be \0. Your programming must simply be correct as there are no protections.

If you are in C++, you should be using basic_string<char>, which is the C++ string type.

[AdrianH]

Hi, It's always good to initialize char array with memset to avoid any memory corruption further ..memset(nameofarray,'\0',sizeof(nameofarray)).

No need. Please read post 10 for further explination.


Adrian

[AdrianH]

This does no good. There are no provisions to force you to stay within array bounds and a zero may not be the correct initial value.

If you are in C, and the char array is to contain a C-string , then only element 0 need be \0. Your programming must simply be correct as there are no protections.

If you are in C++, you should be using basic_string<char>, which is the C++ string type.

memset is valid to use here, just not necessary. '\0' is equal to 0, if it weren't, it would break a lot of code.

You are correct that there are no provisions to keep you from straying outside the bounds of the array except for the definition of a C string, which is that it is null terminated (ends with the last char in the string being '\0'.

basic_string is good for many things, and can be very safe. It is up to the programmer to decide if it is the best thing to do. There are times that effecency requirements may restrict the you from moving to basic_string (though this argument is getting weaker as CPUs get faster).


Adrian