[Tom Bottiglieri]

Originally Posted by amateurrobotguy

Why bother with the int *ptr declaration when it has to be used again in the b= part? This is the example from Wiki.

int *ptr; //ptr is a pointer to the address an 'int' somewhere in memory
int a, b; //compiler chooses where these go in memory, each have an address

a = 10; //set value of a to 10
//pass a by reference to ptr
ptr = &a; //ptr now holds the address of where a is in memory
b = *ptr; //b now holds the value (use *) that ptr points to

In this case, b would be equal to a at the end.
The first line declares a pointer, which is different from a regular variable.
You can do other cool things with this, too.

void idouble(int * input){
   *input *= 2 ;
}

void main(){
    int x ;
    x = 5 ;
    idouble(&x) ;
    print(x);
}

This will print 10.