sprintf (covert int to char[])-Collection of common programming errors

In my program I try to convert a int to a char[20];

I try to do this in the following way:

  char str[20];    
  sprintf(str, "%d", timer);

in which timer is the int.

But when i build this code, i get the following warnings…

Type implicit declaration of function 'sprintf' [-Wimplicit-function-declaration]   
incompatible implicit declaration of built-in function 'sprintf' [enabled by default]   

what does that mean?

note:( i have included string.h and stdlib.h).

great, i added stdio.h to my code and now the warnings dissapeard only to give me a even harder error. Any suggestions?

undefined reference to `_sbrk’

1. You have to #include to use sprintf()

2. you want to make sure you also add reference to

   stdio.h

   see this ref

3. You probably need to put sprintf(str, "%d", timer) inside a function (not on the global part of the source code).

   Something like:

   #include 
   char str[20];
   // SPOT #1
   int f() {
       sprintf(str, "%d", timer); // this won't work if placed on SPOT #1
   }
   

Originally posted 2013-11-09 23:14:02.