String to char[]

[Witchie NL]

Does anyone know how to copy a String into a char array?

 

For instance:

If i have an integer type variable that holds the number 1234567.

And a char temp[10] array.

How do i get the integer into the char array so i have each number in a seperate array position like:

 

temp[0]=1

temp[1]=2

temp[3]=3

temp[4]=4

temp[5]=5

temp[6]=6

temp[7]=7

 

 

At the moment i have this:

String temp = t->Amount;  // t->Amount is an integer
char blah[10];
strncpy(blah, temp, 10);

But this copies the value of the string variable into each array position.

 

So with a string holding 100 that would make:

blah[0]=100

blah[1]=100

blah[2]=100

[Russky]

Well when I did coding last year I remember writing an out put

 

Russky

 

is the same as

 

R+u+s+s+k+y

 

Hope that helps.

[Drake7707]

i dunno if the string is ascii or unicode, but if it is ascii you could use CopyMemory api and p!@#$%^&* the pointer of the string and the pointer of the array

[»Admiral Kirk]

Well, first of all, youll need to specify what language your writing in.... That would be most helpfull. If you are using C++ and the String you speak of is an STL string (which it might not be because STL string is lowercase s) then you would do something like:

 

char temp[20];

string test;

test = "stuff";

strncpy(temp, stuff.c_str(), stuff.length());

 

If were talking some other language, then who knows. Or again, if were not speaking of the STL string class, then once again, who knows Specify ^^

 

P.S.: The Above is begging for a buffer overflow fyi, youll want to check that stuff does not exceed the known length of your char buffer ^^.

[Smong]

You're also asking two different things:

- Copy String to char array.

- Copy each digit of an integer into a char array as integers.

 

Just to make this a bit clearer, these are different:

buf[0] = 0;

buf[0] = '0';

[Witchie NL]

Well, first of all, youll need to specify what language your writing in.... That would be most helpfull. If you are using C++ and the String you speak of is an STL string (which it might not be because STL string is lowercase s) then you would do something like:

 

char temp[20];

string test;

test = "stuff";

strncpy(temp, stuff.c_str(), stuff.length());

 

If were talking some other language, then who knows. Or again, if were not speaking of the STL string class, then once again, who knows Specify ^^

 

P.S.: The Above is begging for a buffer overflow fyi, youll want to check that stuff does not exceed the known length of your char buffer ^^.

 

Im doing this in C++ for mervbot. Mervbot has its own string class included and c_str() isnt included.

Adding at the top isnt working aswell.

[Bak]

My turn!

char buf[10];
int num = 12456;

_snprintf(buf, sizeof(buf) - 1, "%i", num);
buf[sizeof(buf) - 1] = 0;

 

also, smong is right, if you don't want the ascii values you could do:

 

char buf[10];
int num = 12456;

_snprintf(buf, sizeof(buf) - 1, "%i", num);
buf[sizeof(buf) - 1] = 0;

for (int c = 0; buf[c]; ++c)
buf[c] -= '0';

[Samapico]

char temp[20];

string test;

test = "stuff";

strncpy(temp, (char*)stuff, stuff.len);

 

I think this should work with merv

[Smong]

Bak I don't think you need to do the -1 thing on snprintf, it always makes sure it's null-terminated for you. It's just strncpy that needs the null adding manually.

[Witchie NL]

void botInfo::UpdateLvz(Player *p, int Credsadded)
{
Account *t = FindEntree(p->name);

if (!t)
{
	t = new Account();
	t->Owner = p->name;
	t->Credit = InitCred;
			
	Credslist.append(t);

	tell(makeEcho("New Entree created: "+(String)p->name+"."));
}

string temp;
temp = t->Credit - Credsadded;
char cred1[10];
strncpy(cred1, temp.c_str(), temp.length());

string temp2;
temp2 = t->Credit;
char cred2[10];
strncpy(cred2, temp2.c_str(), temp2.length());

for (int i=0; i<10; i++)
{
	int t = i+20;
	sendPrivate(p, ".*objoff "+(String)t+(String)cred1[i]);
	sendPrivate(p, ".*objon " +(String)t+(String)cred2[i]);
}
}

 

To make it a bit easyer: this is what i need to do, What should i change to what?

t=a number between 19 and 30 where the first of those is just a number the second number is a pos on the lvz board and the third number cred# is the number of the lvz.

So 213 would make 2-position 1-number 3.

 

I also tried to use temp.at(i); but somehow i couldnt use that in sendPrivate(), gives an error and then closes mervbot.

Edited September 12, 2007 by Witchie NL

[Witchie NL]

Ok bak's code worked and the buf[sizeof(buf) - 1] = 0; wasnt needed indeed.

 

Now the following:

I have this,

int temp = t->Credit - Credsadded;
char cred1[10];
_snprintf(cred1, sizeof(cred1) - 1, "%i", temp);

for (int c = 0; cred1[c]; ++c)
cred1[c] -= '0';


int temp2 = t->Credit;
char cred2[10];
_snprintf(cred2, sizeof(cred2) - 1, "%i", temp2);

for (int d = 0; cred2[d]; ++d)
cred2[d] -= '0';


for (int i=0; i<10; i++)
{
int t = i+20;

sendPrivate(p, ".*objoff "+(String)t+(String)cred1[i]);
sendPrivate(p, ".*objon " +(String)t+(String)cred2[i]);
}

 

Now it works propperly but if i have a number under the 10 digits it gives a little problem.

 

int a = 12345;

char b[10];

 

youll have...:

 

b0=1;

b1=2;

b2=3;

b3=4;

b4=5;

b6=0;

b7=;

b8=;

b9=;

 

...after the _snprintf();

 

Main question: To make it a bit easyer: this is what i need to do, What should i change to what?

Or if posible: Is there a way to fill up the with 0's?

Edited September 12, 2007 by Witchie NL

[Samapico]

errr, this is Merv right?

 

There are built-in functions to toggle lvz objects that are much more efficient

 

object_target(p); //sets target of the objects to toggle, set to NULL if you want the object to be public

queue_enable(objectID); //do that for every object you want to queue; queue_disable to disable them

toggle_objects(); //toggles all objects queued

 

Now... you want to display each digit of your number; you don't need a string for that

 

Simple version:

int creds = t->Credit - CredsAdded; //or whatever you want to display

for (int i = 0; creds > 0; i++)
{
  int currentdigit = creds % 10; //hold the right-most digit
  queue_enable(i*10 + currentdigit); //depending on how your lvz is made, this is where your ID is calculated, for a digit 'i'
  creds /= 10; //get rid of the right-most digit by dividing by 10
}

Now, if you want to display leading zeros, and hide old objects, you could have:

int creds = t->Credit - CredsAdded; //or whatever you want to display
int oldcreds = ...;

for (int i = 0; i < 10; i++)
{
  int newdigit = creds % 10; //hold the right-most digit
  int olddigit = oldcreds % 10;

  queue_enable(i*10 + newdigit); //depending on how your lvz is made, this is where your ID is calculated, for a digit 'i'
  queue_disable(i*10 + olddigit); 

  creds /= 10; //get rid of the right-most digit by dividing by 10
  oldcreds /= 10;
}

 

 

Hope that helps

[Bak]

Bak I don't think you need to do the -1 thing on snprintf, it always makes sure it's null-terminated for you.

 

The man page says snprintf is always supposed to be null terminiated... but the windows version doesn't live up the the specification. You're right about the -1 though, so it should be:

 

_snprintf(buf, sizeof(buf), "%i", num);
buf[sizeof(buf)] = 0;

 

whereas accoding to the specification you should just be able to do:

 

_snprintf(buf, sizeof(buf), "%i", num);

 

to see the error run this program:

 

#include <stdio.h>

int main()
{
const char* !@#$%^&*o = "!@#$%^&*o";
char buf[5];

_snprintf(buf, sizeof(!@#$%^&*o), "%s",!@#$%^&*o);
//buf[ sizeof(!@#$%^&*o)] = 0;

printf("%i: '%s'\n",sizeof(!@#$%^&*o),buf);

return 0;
}

 

-----------------------------------------------------------------------------------------------------------------------------

 

try this witchie (but sampacio is right about the more efficient way):

 

int temp = t->Credit - Credsadded;
char cred1[10];
_snprintf(cred1, sizeof(cred1) - 1, "%i", temp);

for (int c = 0; cred1[c]; ++c)
cred1[c] -= '0';


int temp2 = t->Credit;
char cred2[10];
_snprintf(cred2, sizeof(cred2) - 1, "%i", temp2);
int len = (int)strlen(cred2);

for (int d = 0; cred2[d]; ++d)
cred2[d] -= '0';


for (int i=0; i<len; i++)
{
int t = i+20;

sendPrivate(p, ".*objoff "+(String)t+(String)cred1[i]);
sendPrivate(p, ".*objon " +(String)t+(String)cred2[i]);
}

[Smong]

I get your point bak. I don't want to beat a dead horse but without -1 you will overrun the buffer and it only happens to work in the test program because you are looking at the size of a char pointer (4) not of the buffer (5).

[Bak]

crap, that's supposed to be sizeof(buf)... heh, well I guess bugs can happen in the simplest of programs.