Страустрап Бьярн
Шрифт:
};
class assoc_iterator {
assoc* cs;
int i;
public:
assoc_iterator(assoc& s) { cs =&s; i = 0; }
pair* operator
{ return (i‹cs-›free) ? &cs-›vec[i++] : 0; }
};
assoc::assoc(int s)
{
max = (s‹16) ? s : 16;
free = 0;
vec = new pair[max];
}
int& assoc::operator[](char* p)
{
register pair* pp;
for (pp = &vec[free-1]; vec‹=pp; pp--)
if (strcmp(p,pp-›name)==0) return pp-›val;
if (free == max) {
pair* nvec = new pair[max*2];
for (int i=0; i‹max; i++) nvec[i] = vec[i];
delete vec;
vec = nvec;
max = 2*max;
}
pp =&vec[free++];
pp-›name = new char[strlen(p)+1];
strcpy(pp-›name,p);
pp-›val = 0;
return pp-›val;
}
main
{
const MAX = 256;
char buf[MAX];
assoc vec(512);
while (cin››buf) vec[buf]++;
assoc_iterator next(vec);
pair* p;
while (p = next)
cout ‹‹ p-›name ‹‹ ": " ‹‹ p-›val ‹‹ "\n";
}
b6_9.cxx
#include ‹stream.hxx›
#include ‹string.h›
extern void exit(int);
class string {
struct srep {
char* s;
int n;
};
srep *p;
public:
string(char *);
string;
string(string&);
string& operator=(char *);
string& operator=(string&);
~string;
char& operator[](int i);
friend ostream& operator‹‹(ostream&, string&);
friend istream& operator››(istream&, string&);
friend int operator==(string&x, char *s)
{ return strcmp(x.p-›s, s) == 0; }
friend int operator==(string&x, string&y)
{ return strcmp(x.p-›s, y.p-›s) == 0; }
friend int operator!=(string&x, char *s)
{return strcmp(x.p-›s, s) != 0;}
friend int operator!=(string&x, string&y)
{return strcmp (x.p-›s, y.p-›s) != 0;}
};
string::string
{
p = new srep;
p-›s = 0;
p-›n = 1;
}
string::string(char* s)
{
p = new srep;
p-›s = new char[strlen(s) +1];
strcpy(p-›s, s);
p-›n = 1;
}
string::string(string& x)
{
x.p-›n++;
p = x.p;
}
string::~string
{
if (--p-›n - 0) {
delete p-›s;
delete p;
}
}
string& string::operator=(char* s)