Из книги Эккеля "Философия С++" (глава 9) (
ссылка)
Stack4.h
Код:
//: C09:Stack4.h
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
// With inlines
#ifndef STACK4_H
#define STACK4_H
#include "../require.h"
class Stack {
struct Link {
void* data;
Link* next;
Link(void* dat, Link* nxt):
data(dat), next(nxt) {}
}* head;
public:
Stack() : head(0) {}
~Stack() {
require(head == 0, "Stack not empty");
}
void push(void* dat) {
head = new Link(dat, head);
}
void* peek() const {
return head ? head->data : 0;
}
void* pop() {
if(head == 0) return 0;
void* result = head->data;
Link* oldHead = head;
head = head->next;
delete oldHead;
return result;
}
};
#endif // STACK4_H ///:~
require.h
Код:
//: :require.h
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
// Test for error conditions in programs
// Local "using namespace std" for old compilers
#ifndef REQUIRE_H
#define REQUIRE_H
#include <cstdio>
#include <cstdlib>
#include <fstream>
#include <string>
inline void require(bool requirement,
const std::string& msg = "Requirement failed"){
using namespace std;
if (!requirement) {
fputs(msg.c_str(), stderr);
fputs("\n", stderr);
exit(1);
}
}
inline void requireArgs(int argc, int args,
const std::string& msg =
"Must use %d arguments") {
using namespace std;
if (argc != args + 1) {
fprintf(stderr, msg.c_str(), args);
fputs("\n", stderr);
exit(1);
}
}
inline void requireMinArgs(int argc, int minArgs,
const std::string& msg =
"Must use at least %d arguments") {
using namespace std;
if(argc < minArgs + 1) {
fprintf(stderr, msg.c_str(), minArgs);
fputs("\n", stderr);
exit(1);
}
}
inline void assure(std::ifstream& in,
const std::string& filename = "") {
using namespace std;
if(!in) {
fprintf(stderr, "Could not open file %s\n",
filename.c_str());
exit(1);
}
}
inline void assure(std::ofstream& out,
const std::string& filename = "") {
using namespace std;
if(!out) {
fprintf(stderr, "Could not open file %s\n",
filename.c_str());
exit(1);
}
}
#endif // REQUIRE_H ///:~
Stack4Test.cpp
Код:
//: C09:Stack4Test.cpp
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 2000
// Copyright notice in Copyright.txt
//{T} Stack4Test.cpp
#include "Stack4.h"
#include "../require.h"
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
int main(int argc, char* argv[]) {
requireArgs(argc, 1); // File name is argument
ifstream in(argv[1]);
assure(in, argv[1]);
Stack textlines;
string line;
// Read file and store lines in the stack:
while(getline(in, line))
textlines.push(new string(line));
// Pop the lines from the stack and print them:
string* s;
while((s = (string*)textlines.pop()) != 0) {
cout << *s << endl;
delete s;
}
} ///:~