Why we have to cout first string outside the while loop

#1

int main()

{

char s[100] ="hello world, this is jainish here. i am a programmer & coder";

char *s_ptr=strtok(s," ");

while(s_ptr!=NULL)
{
	s_ptr=strtok(NULL," ");
	cout<<s_ptr<<" ";
}


return 0;

}

why string hello is not printing in the above code.

#2

For the first call of strtok, you have to send the string to it.This is why it is called outside the loop.
strtok returns a pointer to the character of next token. So the first time it is called, it will point to the first word . In the next call to strtok , the first parameter needs to be NULL so that strtok starts splitting the string from the next token’s starting position it remembers.