Combines multiple C/C++ files into one and copy to clipboard.

cppcp.cpp

#define WIN32_LEAN_AND_MEAN
#include <Windows.h>

#include <cstdlib>
#include <exception>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <stdexcept>
#include <string>
#include <string_view>
#include <unordered_set>

using namespace std;
using namespace filesystem;

[[noreturn]] void IncorrectUsage() {
    cerr << "Incorrect usage";
    exit(1);
}

unordered_set<string> Once;
string Output;

bool IsAnalyzed(const path& pa) {
    return Once.find(canonical(pa).string()) != Once.end();
}

void Insert(const path& pa) {
    Once.emplace(canonical(pa).string());
}

void Analyze(const path& pa) {
    if (IsAnalyzed(pa))
        return;
    ifstream fi(pa);
    string line;
    while (getline(fi, line)) {
        if (line.find("#pragma once") == 0)
            Insert(pa);
        else if (line.find("#include") == 0) {
            auto beg = line.find('"');
            auto end = line.rfind('"');
            if (beg != string::npos && end != string::npos)
                Analyze(pa / ((string_view) line).substr(beg + 1, end - beg - 1));
            else {
                Output += line;
                Output += "\r\n";
            }
        }
        else {
            Output += line;
            Output += "\r\n";
        }
    }
}

int main(int argc, char* argv[]) {
    if (argc != 2) 
        IncorrectUsage();
    try {
        Analyze(argv[1]);
        if (!OpenClipboard(nullptr))
            throw runtime_error("OpenClipboard");
        EmptyClipboard();
        auto h = GlobalAlloc(GMEM_MOVEABLE, Output.size() + 1);
        if (!h) {
            CloseClipboard();
            throw runtime_error("GlobalAlloc");
        }
        auto p = GlobalLock(h);
        memcpy(p, Output.c_str(), Output.size() + 1);
        GlobalUnlock(h);
        SetClipboardData(CF_TEXT, h);
        CloseClipboard();
        cout << Output << endl;
    }
    catch (exception& e) {
        cerr << "Failed: " << e.what() << endl;
        return 1;
    }
    return 0;
}