convert integer to string (atoi?)

lea · 10-10-2002, 07:12 AM

Hi all!

I would like to convert an integer-variable into a string.

* Where do I get atoi (*.h)? resp. how do I apply this function?

* Is there a smarter way (without atoi) to program this:

int age=12;
char string[]="My Age: ";
strcpy(string, itoa(age));

TIA
Lea

Mara · 10-10-2002, 12:14 PM

First thing: atoi converts string to an integer.
You need to use another function. I can't recall an name now, but it's quite easy. When you've got a number, you make a copy of it, divide it by 10 and see what's left (modulo 10). Then you write the right character to a table and to the same with the orginal number divided by 10. You do this until the number is 0.

Ztyx · 10-10-2002, 01:10 PM

This is much simpler:

Code:

#include <stdio.h>

int age=12;
char string[200];
sprintf(string, "My age: %d", age);

The sprintf works as printf although it writes its output to a string instead of stdout (the screen).
For information about the sprintf() function I refer to "man sprintf".

Mara · 10-10-2002, 01:35 PM

Right, it's simplier.

lea · 10-11-2002, 12:51 AM

I like this forum.
Thanks for your replies and the help.
LEA

TheLinuxDuck · 10-11-2002, 03:10 PM

Ztyx is very correct, however, I would highly suggest that you use the snprintf function. This allows you to set a cap length of the string, so that no buffer overruns happen and you get nasty
segfaults or some other such a thing.

Code:

#include <stdio.h>
&nbsp;
int main(void)
{ 
  int retVal, age=12;
  char string[20];
  retVal = snprintf(string, 20, "My age: %d", age);
  if(retVal == -1) 
    printf("Could not store entire length into string\n");
  return 0;
}

TLD

Ztyx · 10-11-2002, 05:16 PM

You're right. It's even better.