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I'm trying to define an array of pointers to strings, as follows:
char* pArray[5];
pArray = "text1";
(pArray+1) = "text1";
(pArray+2) = "text1";
(pArray+3) = "text1";
(pArray+4) = "text1";
Or even like this:
char* pArray[5];
char* pVar1 = "text1";
char* pVar2 = "text1";
char* pVar3 = "text1";
char* pVar4 = "text1";
char* pVar5 = "text1";
(pArray) = pVar1;
(pArray+1) = pVar2;
(pArray+2) = pVar3;
(pArray+3) = pVar4;
(pArray+4) = pVar5;
But there is something wrong in my code (I know that there is something wrong but I've never done this before), could you please show me the correct way to do it? I to do this without using the new operator because I want to allocate the memory from the stack not from the heap.
P.S. I'm not so good at using pointers in C++ or C, so please excuse my bad coding.
Thanks
(a.k.a. Wal2k)
www.wal2k.com
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try this:
const char* pArray[5] = {"text1", "text1", "text1", "text1", "text1"};
-c
For men use, if they have an evil turn, to write it in marble:
and whoso doth us a good turn we write it in dust.
-- Sir Thomas More
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Excellent .. just one more question .. do the strings have to be the same length?
Thanx
(a.k.a. Wal2k)
www.wal2k.com
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no, they can be any length you want.
-c
For men use, if they have an evil turn, to write it in marble:
and whoso doth us a good turn we write it in dust.
-- Sir Thomas More
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Here's another cool trick that will help prevent bugs
const char* pArray[] =
{
"text1",
"text1",
"text1",
"text1",
"text1"
};
const int numArray = sizeof(pArray) / sizeof(char*);
for (int i=0; i<numArray; i++)
{
}
That way if you change the number of items in the array you don't have to remember to update your loop condition.
Todd Smith
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Waleed wrote:
I'm trying to define an array of pointers to strings
Can I ask why your trying to do this???
Regards,
Brian Dela 
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O.K., I'll explain what I want to do. I want to write a functon that is passed a pointer to a string then it checks whether the string starts with specific string constants (prefixes) or not.
e.g.
// PROTOTYPES
BOOL MyFunc(char* pStr);
void main()
{
char *pStr = "some text";
if(MyFunc(pStr))
printf("Correct prefix");
else
printf("wrong prefix");
}
BOOL MyFunc(char* pStr)
{
// my function compares the string to some constants to check that
// it starts with some of them, if the string doesn't it returns FALSE
// the function checks that the string start with one of the following
// strings: John, Michael, George, Donald
// here I want to define all the constant and point to them using the
// array of pointers in order to use a for loop to make the comparison
// e.g. let's imagine that I have the array and points to the right
// string constant ( the name of the array of pointers is
// pArrayOfPointerToStrings , now let's use the for loop
for(int i=0;i<4;++i)
{
// use pArrayOfPointerToStrings[i] and compare it
// to the passed string pStr
}
}
Of course that can be done in many other ways without using the array of pointers, - e.g. using char str[4][10] - but the whole point is that I want to know - learn - how to do this (define an array of pointer to strings and make it actually point to the strings)
(a.k.a. Wal2k)
www.wal2k.com
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You have ot allocate memory to each of the element os the array before you initialize it with anything.
Try this:
char* pArray[5];
pArray[0] = (char*)calloc(strlen("text1")+1,sizeof(char));
pArray[1] = (char*)calloc(strlen("text2")+1,sizeof(char));
pArray[2] = (char*)calloc(strlen("text3")+1,sizeof(char));
pArray[3] = (char*)calloc(strlen("text4")+1,sizeof(char));
pArray[4] = (char*)calloc(strlen("text5")+1,sizeof(char));
pArray[0] = "text1"
pArray[1] = "text2"
pArray[2] = "text3"
pArray[3] = "text4"
pArray[4] = "text5"
Prashant Panigrahi.
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Hey this is no good! If you first allocate and then assign a const char *, the previously allocated memory gets lost and you'll have leaks. It should be:
pArray[0] = (char*)calloc(strlen("text1")+1,sizeof(char));
...
strcpy(pArray[0],"text1");The memory should also be freed when no longer needed. If the guy just needs a const char * array, then no memory allocation is needed and Chris' proposal (a couple of posts above) is the way to go.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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or
*(pArray) = pVar1;
*(pArray+1) = pVar2;
*(pArray+2) = pVar3;
*(pArray+3) = pVar4;
*(pArray+4) = pVar5;
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Waleed wrote:
pArray = "text1";
(pArray+1) = "text1";
You're not dereferencing the array correctly. The first element of pArray is pArray[0], the second is pArray[1], etc. pArray by itself is the entire array, and pArray+1 points past the end of the array.
--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
My really out-of-date homepage
Sonork-100.19012 Acid_Helm
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I've got an edit control with the ES_AUTO*SCROLL styles off, so no more text can be typed past the end of the control. I was trying to detect when this happens programmatically, and I saw that I get a WM_CHAR message indicating a backspace with a repeat count of zero when this happens. Is this documented anywhere, or do you think it's reliable? ... Or is there another way? Thanks.
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I believe parent window receives EN_MAXTEXT notification.
Tomasz Sowinski -- http://www.shooltz.com
Free your mind and your ass will follow.
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ah, wonderful, thanks a lot
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Why am I getting a wierd letter (i.e. - the letter that is showing up is ÿ for me  ) at the end of my appended file when I open it after running this little program, any ideas?
#include <fstream.h>
void main()
{
ifstream inFile;
ofstream outFile;
char file1[80], file2[80];
char c;
cout << "Enter file 1:";
cin >> file1;
cout << "Enter file 2:";
cin >> file2;
inFile.open(file1, ios::in);
outFile.open(file2,ios::app);
while(! inFile.eof())
{
c = inFile.get();
if(c != inFile.eof())
{
outFile << c;
}
}
inFile.close();
outFile.close();
cout << "\nDone.\n";
}
Nick Parker
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Hi There,
It looks like you've got some kind of string memory problem, because ÿ is the 255 charachter - 0xFF. 0xFF, 0x00, 0xFC and 0xCC are often found floating around in unallocated memory, so it looks as if your somehow spitting charachters which are not in the file, check your loop, and how the get() command works. I think this could be your problem. If your still unsure, add this code (just for debugging)
while(! inFile.eof())
{
c = inFile.get();
if(c == 0xFF)
{
}
if(c != inFile.eof())
{
outFile << c;
}
}
Hope thats useful
With time we live, with money we spend!
Joel Holdsworth.
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istream::get returs int, not char. You should change 'c' to int and cast back to char before inserting into outFile:
int c;
...
outFile << (char)c;
Tomasz Sowinski -- http://www.shooltz.com
Free your mind and your ass will follow.
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Whack! Whack! Whack! Whack! Whack! Whack! Whack! Whack! Whack! Whack!
You know what that sound is? It's the sound of me hitting my self in the F^&*%$^%$ head with a large board...
You would think that the compilers now days would know that I actually meant zero
I wanted to use the counter as part of the string I was displaying and the devices I am listing here are enumerated starting at 1 so I just changed the start of the countr without even noticing that it was used to set the iItem.
Thanks for the fast response guys....
I am going to go look for a small rock to climb under now and hide
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I feel kind of silly putting something so simple on here but I am working on an MFC app and am having a little bit of trouble making an Exit button. I tried using the OnClose command like the mainframe uses but it doesn't seem to be working. Any ideas?
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Depends if your application is dialog based or not.
For example if is that the case you can use EndDialog(IDOK)
Carlos Antollini.
Sonork ID 100.10529 cantollini
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Thanks, mine required that I pass an HWND object but that was fairly easy to get. Thanks again.
Gosh I feel like such a freshman.
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AfxGetMainWnd()->PostMessage(WM_CLOSE);
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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The EndDialog thing didn't do exactly what I wanted it to do. It got rid of the dialog but it was still running in the background. This caused a nifty blue screen of death the next time I executed it. This works much better, can't believe I didn't think of it before. Thanks.
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Is there an API that exists where I can specify a main file and then another file, where the second file just gets appended to the first file. I am looking for something like this.
CString m_MainFile = "C:\main.txt";
CString m_AnotherFile = "C:\another.txt";
AppendMyFiles(m_MainFile, m_AnotherFile);
In this case the contents of another.txt are appended to main.txt.
Thanks in advance.
Nick Parker
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