【C】Pointer (3) Run Program Which Uses Pointers

$ gcc –version
gcc (Ubuntu 4.8.4-2ubuntu1~14.04.3) 4.8.4
Copyright (C) 2013 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

#include <stdio.h>

int main()
{
        int a;
        const int b = 10;
        int *p;

        a=1;
        p=&a;

        printf("a's value is %d \n", a);
        printf("a's address is %p \n", &a);
        printf("p's value is %p \n", p);

        a++;

        printf("a's value is %d \n", a);
        printf("a's address is %p \n", &a);
        printf("p's value is %p \n", p);

        p=&b;
        printf("b's value is %d \n", b);
        printf("b's address is %p \n", &b);
        printf("p's value is %p \n", p);

        *p = 11;
        printf("b's value is %d \n", b);
        printf("b's address is %p \n", &b);
        printf("p's value is %p \n", p);

        return 0;

}

$ gcc 03_1.c
03_1.c: In function ‘main’:
03_1.c:22:3: warning: assignment discards ‘const’ qualifier from pointer target type [enabled by default]
p=&b;
^

$ ./a.out
a's value is 1
a's address is 0x7ffc5ccd5ff0
p's value is 0x7ffc5ccd5ff0
a's value is 2
a's address is 0x7ffc5ccd5ff0
p's value is 0x7ffc5ccd5ff0
b's value is 10
b's address is 0x7ffc5ccd5ff4
p's value is 0x7ffc5ccd5ff4
b's value is 11
b's address is 0x7ffc5ccd5ff4
p's value is 0x7ffc5ccd5ff4