Справочное руководство по C++

Страустрап Бьярн

 switch (argc) {

 case 1:

break;

 case 2:

cin = *new istream(strlen(argv[1]),argv[1]);

break;

 default:

error("too many arguments");

return 1;

 }

 // insert predefined names:

 insert("pi")-›value = 3.1415926535897932385;

 insert("e")-›value = 2.7182818284590452354;

 while (1) {

get_token;

if (curr_tok == END) break;

if (curr_tok == PRINT) continue;

cout ‹‹ expr ‹‹ "\n";

 }

 return no_of_errors;

}

b3_2_6a.cxx

extern void strcpy(char *,char *);

extern void exit(int);

extern int strlen(char *);

char *save_string(char* p)

{

 char* s = new char[strlen(p)+1];

 strcpy(s,p);

 return s;

}

int main (int argc, char* argv[])

{

 if (argc ‹ 2) exit(1);

 int size = strlen(argv[1])+1;

 char* p = save_string (argv[1]);

 delete[size] p;

}

b3_2_6b.cxx

#include ‹stream.hxx›

extern void exit(int);

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)

{