Below Example Will Help You In Understanding The Difference:
1)const char *myptr
Ex:
char ch = 'a';
const char *myptr = &ch;
*myptr = 'b' <---- Not Possible
myptr++; <-----Possible
2)char *const myptr
Ex:
char ch = 'a';
const char *myptr = &ch;
*myptr = 'b' <---- Possible
myptr++; <-----Not Possible