strncmp resulting in OutOfRange error

[XNOR]

hi fellow programmers, a bit of help if you will.

I am writing a program to search and replace certain lines/strings in a memo/richedit. Here is the code:
void __fastcall TForm1::Button2Click(TObject *Sender)
{

int i;
int n=0;
int token = 0;

//this sets up some strings so i can do a quick search for the word
char keyword[2][17]={"ZSOLDADDR1Z", "ZSOLDADDR2Z"};
//this allows me to use key codes to use with the caseswitch
enum{ZSOLDADDR1Z, ZSOLDADDR2Z};

//this increments each line
for(n=0; n<RichEdit1->Lines->Count; n++)
{
//this sets up my string for searching
String string=RichEdit1->Lines->Strings[n]+&quot; ~&quot;;
//obviously, the keyword has to strat with 'Z' to make things easy
if(string[1]=='Z')
{
//this is where i search each enum and compare it to the strings. It is also where i get my error.(at the if)
for(i=0; i<=2; i++)
if(strncmp(keyword, &string[n], strlen(keyword))==0)
token=i;

//does the good stuff once keyword is found
switch(token)
{
//this area incomplete, cant get here yet to worry about it
case ZSOLDADDR1Z: RichEdit1->Lines->Strings[n]=Edit2->Text ; break;
case ZSOLDADDR2Z: break;
default: break;
}
}
}
}

In the strncmp where its in the if statement, i have three items. the first two are the items to be compared and the third the lenght to compare. At that point keyword == the enum strings and &string[n] == the line that the pointer is at... considering it gets to ZSOLDADDR1Z, borland kicks me out and points to ThrowIfOutOfRange(idx); in dstring.h.

If you could give me a hint of a reason why this small function is not working, i would be much obliged.

if i need to clarify, please be specific. if i need to shove off, be nice

 

[XNOR]

Uhm, ok. Well, i fixed the problem by just doing a whole new project. Dont ask me why those problems arise... but if you know, please do tell.

Now if i may, ill move away silently to avoid any ridicule due to my buggy code

 

[wimvanherp]

the errors in your code :

first you define a AnsiString named string to read the strings out of your RichEdit :

String string=RichEdit1->Lines->Strings[n]+&quot; ~&quot;;

and later on you use :
if(strncmp(keyword, &string[n], strlen(keyword))==0)

first error : if you use string[n], there is supposed to be an array of string while you only initialised one,

second : strncmp asks for a c_str string (char *), if you want to convert a AnsiString to a c_str you have to use .c_str() for the AnsiString.

Correct would be :
if(strncmp(keyword, string.c_str(), strlen(keyword))==0)

also (a bit earlier) :if(string[1]=='Z')
must be : if (string.c_str()[0]=='Z')

string is the AnsiString you get out of the RichEdit.
string.c_str() is the conversion of that AnsiString to a c_str
string.c_str() gives the character of position i in that string (the first character has index 0)

I know there is a lot of confusion about char* strings (the classical strings of c++) and AnsiStrings, but it is essential.

regards

Wim Vanherp


Wim Vanherp
Wim.Vanherp@myself.com