Code:
const int i=10;
printf("%d",i);
int *j=&i;
*j*=2;
printf("%d",i);
Well I think the compiler might throw a warning in the above code but still would give output 10 20.

Code:
So instead of changing the value with a pointer, do this instead
const int i=10;
printf("%d",i);
int j=i;
j*=2;
printf("%d",j);
How is the above code relevant to changing the value of const .In case you need to change the value of const(even though if that is the case no use of defining the variable as a const) you could only do it with pointer.The above code merely prints.