002
23.04.2004, 10:03 Uhr
(un)wissender
Niveauwart
|
Vielleicht hilft dir das...
| C++: |
#include <iostream>
#include <fstream>
#include <vector>
class DB
{
public:
DB(const char * fileName = 0);
friend std::istream & operator>>(std::istream &in, DB &db);
friend std::ostream & operator<<(std::ostream &out, const DB &db);
//Zum lesen
const int& operator[](size_t index) const;
//Zum schreiben
void addElementAt(size_t index, int element);
private:
std::vector<int> storage;
};
DB::DB(const char * fileName)
{
if(fileName)
{
std::ifstream in(fileName, std::ios::binary | std::ios::in);
in >> *this;
in.close();
}
}
void DB::addElementAt(size_t index, int element)
{
if(storage.size() <= index)
{
storage.resize(index + 1);
}
storage[index] = element;
}
const int& DB::operator[](size_t index) const
{
return storage[index];
}
std::istream & operator>>(std::istream &in, DB &db)
{
int element;
if(in)
in.read(reinterpret_cast<char *>(&element), sizeof(int));
for(unsigned int i = 0; in; ++i)
{
db.addElementAt(i, element);
in.read(reinterpret_cast<char *>(&element), sizeof(int));
}
return in;
}
std::ostream & operator<<(std::ostream &out, const DB &db)
{
typedef std::vector<int>::const_iterator vecIter;
for(vecIter i = db.storage.begin(), end = db.storage.end();
i != end;
++i)
{
out.write(reinterpret_cast<const char *>(&*i), sizeof(int));
}
return out;
}
int main(int argc, char *args[])
{
if(argc > 2)
{
std::ofstream out(args[1], std::ios::binary | std::ios::out);
int testValues[] = { 11, 12, 13, 345};
int testValuesLength = 4;
out.write(reinterpret_cast<const char *>(&testValues[0]),
testValuesLength * sizeof(int));
out.close();
DB db(args[1]);
std::ofstream outResult(args[2], std::ios::binary | std::ios::out);
outResult << db;
outResult.close();
}
return 0;
}
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Wer früher stirbt ist länger tot.
Dieser Post wurde am 23.04.2004 um 11:18 Uhr von Pablo editiert. |
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