Справочное руководство по C++

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

 }

 return 0; // not found

}

void print_in_order(intset* set)

{

 int var;

 set-›iterate(var);

 while (set-›ok(var)) cout ‹‹ set-›next(var) ‹‹ "\n";

}