Strtok in C++ abnormal behaviour
c++
Solution
char delims[] = {' ',','};
should be
char delims[] = " ,";
You're passing a list of chars instead of a `char *` bearing the list of delimiters to use, hence unexpected behaviour because `strtok` expects a 0-terminated string. In your case, `strtok` goes "in the woods" and tokenizes with anything after the declared array.
Problem
I am trying to use strtok in C++ to get tokens of a string. But, I see that in one ur of 5 run the tokens being returned by function are incorrect. Can someone pls, suggest what can be the problem? Sample code reproducing the issue I am facing: ``` #include<iostream> #include<vector> #include<cstring> using namespace std; #define DEBUG(x) cout<<x<<endl; void split(const string &s, const char* delim, vector<string> & v) { DEBUG("Input string to split:"<<s); // to avoid modifying original string first duplicate the original string and return a char pointer then free the memory char * dup = strdup(s.c_str()); DEBUG("dup is:"<<dup); int i=0; char* token = strtok(dup,delim); while(token != NULL) { DEBUG("token is:"<<string(token)); v.push_back(string(token)); // the call is treated as a subsequent calls to strtok: // the function continues from where it left in previous invocation token = strtok(NULL,delim); } free(dup); } int main() { string a ="MOVC R1,R1,#434"; vector<string> tokens; char delims[] = {' ',','}; split(a,delims,tokens); return 0; } ``` Sample output: ``` mayank@Mayank:~/Documents/practice$ ./a.out Input string to split:MOVC R1,R1,#434 dup is:MOVC R1,R1,#434 token is:MOVC token is:R1 token is:R1 token is:#434 mayank@Mayank:~/Documents/practice$ ./a.out Input string to split:MOVC R1,R1,#434 dup is:MOVC R1,R1,#434 token is:MO token is:C token is:R1 token is:R1 token is:#434 ``` As you can see in second run the tokens created are `MO C R1 R1 #434` and not `MOVC R1 R1 #434` I tried checking library code too but not able to figure out the mistake. Please help. EDIT1: My gcc version is: `gcc version 6.2.0 20161005 (Ubuntu 6.2.0-5ubuntu12)`