ch10l01.txt

《Web编程专家指南》

Listing 10.1 Automatically update a document.

/*
$HEADER:$
ACCESS.CPP

A quick-and-dirty program that demonstrates automatic updating of
documents, in particular, access counts.

Written for InterActivity 
by Larry O'Brien.
Consult article for discussion/comments.
(c) 1995, Larry O'Brien

*/

/*
This program does not bother to lock the COUNT_FILE, so there may be
multiple reads and writes on a sufficiently busy server
*/

#include <stdlib.h>
#include <fstream.h>

const char* COUNT_FILE=count.txt
int main(int, char**){
    ifstream inputFile(COUNT_FILE);
    if (inputFile != NULL){
        unsigned long count;
        inputFile>>count;
        inputFile.close();
        cout<<count;
        ofstream outputFile(COUNT_FILE);
        if(outputFile != NULL){
            outputFile<<++count;
            outputFile.close();
        }else{
            return EXIT_FAILURE;
        }
        return EXIT_SUCCESS;
    }else{
        return EXIT_FAILURE;
    }
}