(C++) Find a ZIP Entry by EntryID Using EntryById

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This example demonstrates how to use the EntryById method to retrieve a ZIP entry using its unique EntryID.

Each ZipEntry object has an EntryID property that uniquely identifies the entry within the currently open ZIP object.

This is useful when:

• An application stores EntryID values for later use
• ZIP entries need to be retrieved without searching by filename
• Multiple entries may have similar names or paths

The example:

• Opens a ZIP archive
• Retrieves an entry using EntryAt
• Saves the entry's EntryID
• Uses EntryById to retrieve the same entry later

Note: This example requires Chilkat v11.0.0 or greater.

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#include <CkZip.h>
#include <CkZipEntry.h>

void ChilkatSample(void)
    {
    bool success = false;

    success = false;

    // Open an existing ZIP archive.
    CkZip zip;

    success = zip.OpenZip("example.zip");
    if (success == false) {
        std::cout << zip.lastErrorText() << "\r\n";
        return;
    }

    // Retrieve the first entry in the ZIP archive.
    CkZipEntry entry;

    success = zip.EntryAt(0,entry);
    if (success == false) {
        std::cout << zip.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Original entry:" << "\r\n";
    std::cout << "  FileName: " << entry.fileName() << "\r\n";
    std::cout << "  EntryID: " << entry.get_EntryID() << "\r\n";
    std::cout << "" << "\r\n";

    // Save the EntryID for later use.
    int entryId = entry.get_EntryID();

    // Create another ZipEntry object.
    CkZipEntry entry2;

    // Retrieve the same entry using EntryById.
    success = zip.EntryById(entryId,entry2);
    if (success == false) {
        std::cout << zip.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Entry retrieved by EntryID:" << "\r\n";
    std::cout << "  FileName: " << entry2.fileName() << "\r\n";
    std::cout << "  EntryID: " << entry2.get_EntryID() << "\r\n";
    std::cout << "" << "\r\n";

    // The filenames and EntryID values should match.
    zip.CloseZip();

    std::cout << "Done." << "\r\n";
    }