c - atoi() returning strange value -

i'm getting strange behavior out of atoi command. trying find 2 values out of range format [1:2] string being created done dynamic string allocating macro (if sasprintf throws you) read in file @ projects end, however. anyway, seem parsing string correctly, given correct values of token , token2. i'm confused, however, why calling atoi on token2 give me gibberish answer. also, found out in midst of strtok deprecated, haven't bothered switching yet, until solve bug.

char *token; char *token2;  int lsb = 0; int msb = 0;     char *str = null;  sasprintf(str,"[4:0]");  token = strtok(str,"["); if(token != null) {     token = strtok(token,":");     msb = atoi(token);     printf("%d\n", msb);     token2 = strtok(null,"]");     puts(token2);      lsb = atoi(token2);     printf("%d\n",token2); } 

output

4

0

19853443

i think, need change

  printf("%d\n",token2); 

to

  printf("%d\n",lsb); 

token2 char * , cannot print using %d. invokes undefined behavior

that said, check return value of strtok() against null. also, strtod() better alternative atoi().