The problem is that you’re attempting to modify a string literal. Doing so causes your program’s behavior to be undefined. Saying that you’re not allowed to modify a string literal is an oversimplification. Saying that string literals are const is incorrect; they’re not. WARNING : Digression follows. The string literal “this is a test” is of an expression of type char[15] (14 … Read more
Internal implementation of strtok has already been discussed here: How does strtok() split the string into tokens in C? In your type of implementation ( calling it your type because it is quite different from the actual one), you have not allocated any memory dynamically to the local variable ‘W’. So when you return it, … Read more
Why do we use NULL in strok() function? What does this program do when *h is pointing to a string?
I found this sample program which explains the strtok function: However, I don’t see how this is possible to work. How is it possible that pch = strtok (NULL, ” ,.-“); returns a new token. I mean, we are calling strtokwith NULL . This doesen’t make a lot sense to me.
Assuming that earlier code has already split up the line into individual numbers, then the check you want is strtol will never set endtoken to a null pointer; it will set it to point to the first character that is not a digit. If that character is the NUL string terminator (note the slightly different … Read more
The documentation for strtok_r is quite clear. The strtok_r() function is a reentrant version strtok(). The saveptr argument is a pointer to a char * variable that is used internally by strtok_r() in order to maintain context between successive calls that parse the same string. On the first call to strtok_r(), str should point to the string … Read more
strtok() divides the string into tokens. i.e. starting from any one of the delimiter to next one would be your one token. In your case, the starting token will be from “-” and end with next space ” “. Then next token will start from ” ” and end with “,”. Here you get “This” … Read more