How to convert an INTEGER to STRING - C++ Linux

Hello william_jwd.

I got this after using your code:

`itoa' undeclared (first use this function)

Any suggestion ? Do I need to incude some class ?

03.25.2004 at 04:07AM PST, ID: 10676139

Rank: Master

Hi probine,
You could use stringstream:

std::stringstream my_stringstream;
my_stringstream << i;

message = my_stringstream.str();

Cheers,

Stefan

03.25.2004 at 04:07AM PST, ID: 10676142

Rank: Master

probine,
> `itoa' undeclared (first use this function)
>
> Any suggestion ? Do I need to incude some class ?

itoa() is C API. Just do:

#include <stdlib.h>

Accepted Solution

03.25.2004 at 04:10AM PST, ID: 10676162

william_jwd:

you should include stdlib.h

Assisted Solution

03.25.2004 at 04:21AM PST, ID: 10676219

My program:
********************
#include
#include <stdlib.h>
using namespace std;

int main()
{
int i = 0;
string message = "";
message = itoa(i);
return 1;
}
**********************

When trying to compile with: g++ test.cpp -o test I get this error:
**********************
`itoa' undeclared (first use this function)

03.25.2004 at 04:24AM PST, ID: 10676246

Hi stefan73.

When trying to compile with streamstring I get this:

aggregate `std::stringstream my_stringstream' has incomplete type and cannot be defined

Do I need to include any specific class ?

03.25.2004 at 05:12AM PST, ID: 10676571

Rank: Guru

What compiler are you using?

For Microsoft, the function is

char *_itoa( int value, char *string, int radix);

Note the underscore.

Parameters:

value :Number to be converted.
string :String result.
radix :Base of value; must be in the range 2 36.

So do something like

int i = 123;
char buf[100];
_itoa(i, buf, 10);

buf now contains the string.

03.25.2004 at 05:16AM PST, ID: 10676612

FORGET IT..... I SAID LINUX ... Let me ask this now:

I have a program:

char * message;
string temp="HELLO"

How do I put the value "HELLO" in message ?

03.25.2004 at 05:17AM PST, ID: 10676618

Rank: Master

probine,
> Do I need to include any specific class ?

Yes, <sstream>

03.25.2004 at 05:22AM PST, ID: 10676662

Rank: Guru

> FORGET IT..... I SAID LINUX

Sorry, I missed that in the title.

> How do I put the value "HELLO" in message ?

message = temp.c_str();

03.25.2004 at 05:25AM PST, ID: 10676686

Rank: Guru

It needs to be const unless you cast it:

const char *message = temp.c_str();

or

char *message = (char *)temp.c_str();

The second method is dangerous if you plan on changing the contents of message.

03.25.2004 at 05:25AM PST, ID: 10676687

Rank: Master

> itoa() is C API. Just do:

Ouch, it's atoi, not itoa...

For itoa, you'll need sprintf(), which is not the C++ way to do it:

char* itoa(int input){
static char buffer[16];

snprintf(buffer,sizeof(buffer),"%d",input);

return buffer;
}

(using snprintf here to avoid buffer overflows)

03.25.2004 at 05:27AM PST, ID: 10676701

To WAYSIDE:

While trying to compile:

invalid conversion from `const char*' to `char*'

03.25.2004 at 05:35AM PST, ID: 10676762

Rank: Guru

Can you post your code?

03.25.2004 at 05:50AM PST, ID: 10676890

My code is simple:
******************
#include
using namespace std;

int main()
{
char * message;
string temp = "HELLO";
// Here "message" should get the word "HELLO" .... how ?
return 1;
}
**********************

How do I make my "message" to get the value of temp, so when I say:

cout << message

then I get "HELLO" ?

03.25.2004 at 05:56AM PST, ID: 10676937

Rank: Master

probine,
> How do I make my "message" to get the value of temp, so when I say:
>
> cout << message
>
> then I get "HELLO" ?

message=temp.c_str();

03.25.2004 at 05:58AM PST, ID: 10676950

william_jwd:

Try this,

#include
using namespace std;

int main()
{
char * message;
string temp = "HELLO";
strcpy(message, temp);
// Here "message" should get the word "HELLO" .... how ?
return 1;
}

03.25.2004 at 06:06AM PST, ID: 10677024