Program to show Concept of Pointers In C

int c = 10;
int c2 = 20;

/* define a pointer and points to an constant integer.
pc can point to another integer but you cannot change the 
content of it */

const int *pc = &c;

/* pc++; */ /* cause error */

printf("value of pc is %d\n",pc);

pc = &c2;

printf("value of pc is %d\n",pc);

/* define a constant pointer and points to an integer. 
py only can point to y and its memory address cannot be changed
you can change its content */

int y = 10;
int y2 = 20;

int const *py = &y;

*py++;/* it is ok */
printf("value of y is %d\n",y);

/* py = &y2; */ /* cause error */