Справочное руководство по C++ — страница 38 из 41

void out_of_store()
{

 cout ‹‹ "operator new failed: out of store\n";
 exit(1);
}

typedef void (*PF)();

extern PF set_new_handler(PF);

main()
{
 set_new_handler(&out_of_store);
 char *p = new char[100000000];
 cout ‹‹ "done, p = " ‹‹ long(p) ‹‹ "\n";
}

b4_6_8.cxx

// This version of the program does not assume sizeof(int) == sizeof(char*)!

#include ‹stream.hxx›
#include ‹stdarg.hxx›

extern void exit(int);
void error (int …);

main(int argc, char* argv[])
{
 switch (argc) {
 case 1:
  error(0,argv[0],(char*)0);
  break;
 case 2:
  error(0,argv[0],argv[1],(char*)0);
  break;
 default:
  error(1,"with",dec(argc-1),"arguments",(char*)0);
 }
}

void error(int n …)
{
 va_list ap;
 va_start(ap,n);

 for (;;) {
  char *p = va_arg(ap,char*);
  if (p == 0) break;
  cerr ‹‹ p ‹‹ " ";
 }

 va_end(ap);

 cerr ‹‹ "\n";
 if (n) exit(n);
}

b4_6_9.cxx

#include ‹stream.hxx›

struct user {
 char *name;
 char* id;
 int dept;
};

typedef user* Puser;

user heads[] = {
 "Mcilroy M.D", "doug", 11271,
 "Aho A.V.", "ava", 11272,
 "Weinberger P.J.", "pjw", 11273,
 "Schryer N.L.", "nls", 11274,
 "Schryer N.L.", "nls", 11275,
 "Kernighan B.W.", "bwk", 11276
};

typedef int (*CFT)(char*,char*);

void sort(char* base, unsigned n, int sz, CFT cmp)
{
 for (int i=0; i‹n-1; i++)
  for (int j=n-1; i‹j; j--) {
   char* pj = base+j*sz;
   char *pj1 = pj-sz;
   if ((*cmp)(pj,pj1) ‹ 0)
    // swap b[j] and b[j-1]
    for (int k=0; k‹sz; k++) {
     char temp = pj[k];
     pj[k] = pj1[k];
     pj1[k] = temp;
    }
  }
}

void print_id(Puser v, int n)
{
 for (int i=0; i‹n; i++)
  cout ‹‹ v[i].name ‹‹ "\t"
   ‹‹ v[i].id ‹‹ "\t"
   ‹‹ v[i].dept ‹‹ "\n";
}
extern int strcmp(char*, char*);

int cmp1(char* p, char* q)
{
 return strcmp(Puser(p)-›name, Puser(q)-›name);
}

int cmp2(char* p, char* q)
{
 return Puser(p)-›dept - Puser(q)-›dept;
}

main ()
{
 sort((char*)heads,6,sizeof(user),cmp1);
 print_id(heads,6);
 cout ‹‹ "\n";
 sort ((char*)heads,6,sizeof(user),cmp2);
 print_id(heads,6); // in department number order
}

b5_3_2.cxx

#include ‹stream.hxx›

class intset {
 int cursize, maxsize;
 int *x;
public:
 intset(int m, int n);
 ~intset();

 int member(int t);
 void insert(int t);

 void iterate(int& i) { i = 0; }
 int ok(int& i) { return i‹cursize; }
 int next(int& i) { return x[i++]; }
};

extern void exit (int);

void error(char *s)
{
 cout ‹‹ "set: " ‹‹ s ‹‹ "\n";
 exit(1);
}

extern int atoi(char *);

extern int rand();

int randint (int u) // in the range 1…u
{
 int r = rand();
 if (r ‹ 0) r = -r;
 return 1 + r%u;
}

intset::intset(int m, int n)
{
 if (m‹1 || n‹m) error("illegal intset size");
 cursize = 0;
 maxsize = m;
 x = new int[maxsize];
}

intset::~intset()
{
 delete x;
}

void intset::insert(int t)
{
 if (++cursize › maxsize) error("too many elements");
 int i = cursize-1;
 x[i] = t;

while (i›0 && x[i-1]›x[i]) {
 int t = x[i];
 x[i] = x[i-1];
 x[i-1] = t;
 i--;
 }
}

int intset::member(int t)
{
 int l = 0;
 int u = cursize-1;

 int m =0;
 while (l ‹= u) {
  m = (l+u)/2;
  if (t ‹ x[m])
   u = m-1;
  else if (t › x[m])
   l = m+1;
  else
   return 1; // found
 }