c: when using a pointer as input in a function incrementing the pointers value by using *pointer++ doesn't work -

while learning c (i new it), playing around pointers. here can see code:

#include <stdio.h>  void change(int *i) {     *i += 1;   }  int main() {        int num = 3;      printf("%d\n", num);     change(&num);     printf("%d\n", num);      return 0; } 

my aim replace incrementing num value without reassigning so:

num = change(num); 

that's why passing memory location of num using &: used pointer. before version in code same. thing different said *i++; instead of saying *i += 1;

now question why can't *i++?

now question why can't *i++

due operator precedence, *i++ same *(i++).

*(i++); 

is equivalent to:

int* temp = i;  // store old pointer in temporary variable. i++;            // increment pointer *temp;          // dereference old pointer value, noop. 

that not want. need use (*i)++ or ++(*i). these dereference pointer first , increment value of object pointer points to.