Listing 1 Using srbk

void *sbrk(int n);      // prototype for sbrk

char *p,*q;             // two pointers for allocated
                              blocks
p = (char *)sbrk(100);  // allocate a 100-byte block
q = (char *)sbrk(200);  // allocate a 200-byte block

sbrk(-200);             // free the 200-byte block
sbrk(-100);             // free the 100-byte block