C how to convert an integer to string?

totti10 · 10-30-2004, 09:21 PM

what a noob question, but i really do not know how to do it.
for string to integer, we can use atoi,but how about integer to string.
thankx in advance.

Dodgeram01 · 10-30-2004, 09:37 PM

Looks like sprintf() is the function to investigate, although I am not that familiar with C/C++, so I may be off.

aluser · 10-30-2004, 09:56 PM

yeah, it's a messy problem. The problem with sprintf or snprintf is that you need to figure out what is the longest string your int could turn into, so you can make the right size array. If you're on linux, you might be able to do

Code:

#define _GNU_SOURCE
#include <stdio.h>
...
char *s;
asprintf(&s, "%d", myint);
...
free(s);

Still not very pretty.

itsme86 · 10-30-2004, 10:11 PM

I would just use snprintf():

Code:

int main(void)
{
  int num=86;
  char buf[50];

  snprintf(buf, 50, "%d", num);
  return 0;
}

AnanthaP · 10-31-2004, 09:30 AM

Possible pseudo code:
Quotient=InVal;
OutStr="";
While Quotient > 10 {
Reminder=(Quotient \ 10) /* Quotient mod 10 */
OutStr=Reminder+OutString; /* strcat */
Quotient = (Quotient - Reminder) / 10;
}
If Quotient > 0 {
OutStr=Quotient+OutString; /* strcat */
}

End

Nerox · 10-31-2004, 12:38 PM

Due to itoa() doesn't exist (i think), you must use sprintf() function as described above.

totti10 · 10-31-2004, 01:43 PM

i successfully done it using snprintf,thxs lot guys.

karlan · 11-04-2004, 11:45 PM

yes, itoa does exist.

arpan · 11-10-2005, 03:02 AM

itoa() function is only provided in Turbo C but not in Linux

TruongAn · 11-10-2005, 04:46 AM

sprintf is a C function.
But I am going to ask for C++.
How can I do it.

dmail · 11-10-2005, 05:49 AM

for c++ just use a func like so

Code:

#include <sstream>
#include <iostream>
using std::ostringstream;
using std::flush;
using std::string;

string int2string(int num)
{
  ostringstream mystream; 
  mystream << num << flush; 
  return(mystream.str()); 
}