Re: basic c question about char *

The three line example you presented would work, but beware, you only allocated 20 bytes and you have more than that in your message. C will let you get yourself into a lot of trouble with simple mistakes like that.

You will need to "manually" allocate a buffer somehow, as you have done, no little cute shortcuts like your one-line example, like you could do in Java or other languages.

If you knew your message would always be built from a string and an int, you could make your function accept those arguments like

Void myFunction(char *message, int myInt)

and then build your message within myFunction, but I don't think that's what you were looking for.

-Marty

-----Original Message-----

From: Lim Hock-Chai
Sent: Thursday, June 12, 2008 10:59 AM
To: C programming iSeries / AS400
Subject: Re: [C400-L] basic c question about char *


Thank you for all the reply. Now I've a better understanding of char *.


One more question:

Void myFunction(char *message)

myFunction("my static message");

// above function call is pretty straight forward. But what if I need
to pass non static message to it? Is there a way to do it without
having to create a char * or char [] variable. Something like this (I
know the syntax is not correct):

myFunction("my static message" + myInt);


Or do I have to do

char myMessage[20];
sprintf(myMessage, "my non Static message %i", myInt);
myFunction(myMessage);




-----Original Message-----
From: c400-l-bounces+lim.hock-chai=usamobility.com@xxxxxxxxxxxx
[mailto:c400-l-bounces+lim.hock-chai=usamobility.com@xxxxxxxxxxxx] On
Behalf Of Lim Hock-Chai
Sent: Wednesday, June 11, 2008 4:36 PM
To: C programming iSeries / AS400
Subject: [C400-L] basic c question about char *

can somebody help me understand how char * work?

char * s1;
s1 = "assign a value";
s1 = "assign another value"; //does c auto deallocate storage and
reallocate a longer one for this assignment?

. . .



char * s1
int myInt = 10;

sprintf(s1, "test %i", myInt); //why is s1 contains *null after this
assignment?




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