为什么我的 c 程序将字符串拆分为标记什么都不打印

Question

I have code in C for splitting a sample string into tokens using the strtok() function. I seem to have followed everything by the book but my CLion compiler does not print the individual string tokens and exits the script with this code Process finished with exit code -1073741819 (0xC0000005) . Below is how I am trying to split the string, help me debug the issue.

//declare and assign the sentence I need to split
char * sentence ="Cat,Dog,Lion";
//declare and assign the delimiter 
char * delim=",";
//get the first token
char * token = strtok(sentence, delim);
while(token!= NULL){
     //print a single string token
      printf("%s",token);
      //reset the loop for the iteration to continue
      token = strtok(NULL,delim);
    }

Answer 1

The function strtok will write null characters into the string pointed to by its first argument. Therefore, that string must be writable. However, you are supplying a string literal , which is read-only. Attempting to write to a string literal will invoke undefined behavior .

The simplest fix to your problem would therefore be to change the line

char * sentence ="Cat,Dog,Lion";

to:

char sentence[] = "Cat,Dog,Lion";

That way, sentence will be a writable array, instead of a pointer to a string literal.