why a pointer value is assigned before the increment operation is performed

Question

Why does *p++ first assign the value to i and then increment the p pointer, even though ++ post-increment has a higher precedence, and associativity is from Right-to-Left?

int main()
{
    int a[]={55,66,25,35,45};
    int i;
    int *p=&a;
    printf("%u \n",p);
    i=*p++;
    printf(" %u  %d",p,i);
    printf("\n %d",*p);

    return 0;
}

4056
4060 55
66

Answer 1

The semantics of the postfix ++ operator are that the expression p++ evaluates to the current value of p, and as a side effect p is incremented. Effectively, i = *p++; is the same as

i = *p;
p++;

The semantics of the prefix ++ operator are that the expression evaluates to the current value of p plus one, and as a side effect p is incremented. i = *++p; would effectively be the same as

i = *(p + 1);
p++;

Precedence does not control order of evaluation - it only controls parsing (which operators are grouped with which operands).