C pointers - Point to the same address

Question

#include 
#include 

void foo(int *a, int *b);

void foo(int *a, int *b) {
    *a = 5;
    *b = 6;
    a = b;
}

int main(void) {
    int          


        

Answer 1

Using a pseudo-memory map,

In main(),

    a      b
 --------------
|  5   |   6   | <- data
 --------------
 [1000]  [1004]  <- address

In the function foo(),

    a        b      ( local to foo(), different from the a & b in main() )
 ----------------
|  1000  | 1004  | <- data
 ----------------
  [2000]   [2004]  <- address

So, when in foo()'s scope,

*a = 5;   // store 5 in int variable a
*b = 6;   // store 6 in int variable b
 a = b;   // copies contents of pointer variable b to a

So the final map in foo()'s scope is:

    a        b
 ----------------
|  1004  | 1004  | <- data
 ----------------
  [2000]   [2004]  <- address