c - How to find the indices at which strtok() splits the string? -

I was using the strtok () function in C. It gives the pointer on those places where this string splits.

  int main () {char s [100] = "ABCD"; Four * p; P = stroke (S, ""); While (p! = Null) {p = stroke (null, "."); // do something} return 0; }   
 How can I get an index that is divided (preferably continuous time)?   
 
 
 To find the pointer:  
  ptrdiff_t index = p - S;   
 On one side: Show your actual code -  s = "A B C D"  will not be compiled.