#include <stdio.h>
#include <stdlib.h>

// an example of a function taking as input a pointer to a pointer.
void foo(char ** b)
{
  *b = (char *) malloc(sizeof(char) * 6);
  (*b)[0] = 'h';
  (*b)[1] = 'e';
  (*b)[2] = 'l';
  (*b)[3] = 'l';
  (*b)[4] = 'o';
  (*b)[5] = 0;
}


int main()
{
  char * a = "john";
  printf("before calling foo:\n");
  printf("a = %s\n\n", a);
  foo(&a);

  // note that, in contrast to example7.cpp, the value of a
  // is different after calling the foo function
  printf("after calling foo:\n");
  printf("a = %s\n", a);
}