Question/Issue how do I implement the console system from the demo.cpp file?

[PsychoCoffee]

Hello!
I am trying to implement the simple code for the console from the demo cpp file, but I can't seem to get it to work.
I'm trying to put it in a seperate script named Console.cpp and Console.h, but the code (which is a bit confusing to me) is a struct, and Not sure how I should correctly put it in a script which can be called from everywhere else...

I did try removing the struct and making every function inside the struct it's own void but it's giving me a unresolved external symbol error.

I was reading the FAQ and such but I couldn't find a guide to using the code from the demo in your own project.

Example (basically, I copied the whole region/marked area and pasted it in, without the struct):

// A.cpp

#include "Console.h"
void Console::StartDebugConsole()
{
    ClearLog();
    memset(InputBuf, 0, sizeof(InputBuf));
    HistoryPos = -1;

    // "CLASSIFY" is here to provide the test case where "C"+[tab] completes to "CL" and display multiple matches.
    Commands.push_back("HELP");
    Commands.push_back("HISTORY");
    Commands.push_back("CLEAR");
    Commands.push_back("CLASSIFY");
    AutoScroll = true;
    ScrollToBottom = false;
    AddLog("Welcome to Dear ImGui!");
}
void Console::EndDebugConsole()
{
    ClearLog();
    for (int i = 0; i < History.Size; i++)
        free(History[i]);
}

void Console::ClearLog()
{
    for (int i = 0; i < Items.Size; i++)
        free(Items[i]);
    Items.clear();
}

void Console::AddLog(const char* fmt, ...) IM_FMTARGS(2)
{
    // FIXME-OPT
    char buf[1024];
    va_list args;
    va_start(args, fmt);
    vsnprintf(buf, IM_ARRAYSIZE(buf), fmt, args);
    buf[IM_ARRAYSIZE(buf) - 1] = 0;
    va_end(args);
    Items.push_back(Strdup(buf));
}

void Console::ExecCommand(const char* command_line)
{
    AddLog("# %s\n", command_line);

    HistoryPos = -1;
    for (int i = History.Size - 1; i >= 0; i--)
        if (Stricmp(History[i], command_line) == 0)
        {
            free(History[i]);
            History.erase(History.begin() + i);
            break;
        }
    History.push_back(Strdup(command_line));

    // Process command
    if (Stricmp(command_line, "CLEAR") == 0)
    {
        ClearLog();
    }
    else if (Stricmp(command_line, "HELP") == 0)
    {
        AddLog("Commands:");
        for (int i = 0; i < Commands.Size; i++)
            AddLog("- %s", Commands[i]);
    }
    else if (Stricmp(command_line, "HISTORY") == 0)
    {
        int first = History.Size - 10;
        for (int i = first > 0 ? first : 0; i < History.Size; i++)
            AddLog("%3d: %s\n", i, History[i]);
    }
    else
    {
        AddLog("Unknown command: '%s'\n", command_line);
    }

    // On command input, we scroll to bottom even if AutoScroll==false
    ScrollToBottom = true;
}

int Console::TextEditCallbackStub(ImGuiInputTextCallbackData* data)
{
    ExampleAppConsole* console = (ExampleAppConsole*)data->UserData;
    return console->TextEditCallback(data);
}

int Console::TextEditCallback(ImGuiInputTextCallbackData* data)
{
    switch (data->EventFlag)
    {
    case ImGuiInputTextFlags_CallbackCompletion:
    {
        const char* word_end = data->Buf + data->CursorPos;
        const char* word_start = word_end;
        while (word_start > data->Buf)
        {
            const char c = word_start[-1];
            if (c == ' ' || c == '\t' || c == ',' || c == ';')
                break;
            word_start--;
        }
        ImVector<const char*> candidates;
        for (int i = 0; i < Commands.Size; i++)
            if (Strnicmp(Commands[i], word_start, (int)(word_end - word_start)) == 0)
                candidates.push_back(Commands[i]);

        if (candidates.Size == 0)
        {
            // No match
            AddLog("No match for \"%.*s\"!\n", (int)(word_end - word_start), word_start);
        }
        else if (candidates.Size == 1)
        {
            data->DeleteChars((int)(word_start - data->Buf), (int)(word_end - word_start));
            data->InsertChars(data->CursorPos, candidates[0]);
            data->InsertChars(data->CursorPos, " ");
        }
        else
        {
            int match_len = (int)(word_end - word_start);
            for (;;)
            {
                int c = 0;
                bool all_candidates_matches = true;
                for (int i = 0; i < candidates.Size && all_candidates_matches; i++)
                    if (i == 0)
                        c = toupper(candidates[i][match_len]);
                    else if (c == 0 || c != toupper(candidates[i][match_len]))
                        all_candidates_matches = false;
                if (!all_candidates_matches)
                    break;
                match_len++;
            }

            if (match_len > 0)
            {
                data->DeleteChars((int)(word_start - data->Buf), (int)(word_end - word_start));
                data->InsertChars(data->CursorPos, candidates[0], candidates[0] + match_len);
            }

            // List matches
            AddLog("Possible matches:\n");
            for (int i = 0; i < candidates.Size; i++)
                AddLog("- %s\n", candidates[i]);
        }

        break;
    }
    case ImGuiInputTextFlags_CallbackHistory:
    {
        // Example of HISTORY
        const int prev_history_pos = HistoryPos;
        if (data->EventKey == ImGuiKey_UpArrow)
        {
            if (HistoryPos == -1)
                HistoryPos = History.Size - 1;
            else if (HistoryPos > 0)
                HistoryPos--;
        }
        else if (data->EventKey == ImGuiKey_DownArrow)
        {
            if (HistoryPos != -1)
                if (++HistoryPos >= History.Size)
                    HistoryPos = -1;
        }
        if (prev_history_pos != HistoryPos)
        {
            const char* history_str = (HistoryPos >= 0) ? History[HistoryPos] : "";
            data->DeleteChars(0, data->BufTextLen);
            data->InsertChars(0, history_str);
        }
    }
    }
    return 0;
}

void Console::Draw(const char* title, bool* p_open)
{
    ImGui::SetNextWindowSize(ImVec2(520, 600), ImGuiCond_FirstUseEver);
    if (!ImGui::Begin(title, p_open))
    {
        ImGui::End();
        return;
    }
    if (ImGui::BeginPopupContextItem())
    {
        if (ImGui::MenuItem("Close Console"))
            *p_open = false;
        ImGui::EndPopup();
    }
    if (ImGui::SmallButton("Add Debug Text")) { AddLog("%d some text", Items.Size); AddLog("some more text"); AddLog("display very important message here!"); }
    ImGui::SameLine();
    if (ImGui::SmallButton("Add Debug Error")) { AddLog("[error] something went wrong"); }
    ImGui::SameLine();
    if (ImGui::SmallButton("Clear")) { ClearLog(); }
    ImGui::SameLine();
    bool copy_to_clipboard = ImGui::SmallButton("Copy");
    const float footer_height_to_reserve = ImGui::GetStyle().ItemSpacing.y + ImGui::GetFrameHeightWithSpacing();
    if (ImGui::BeginChild("ScrollingRegion", ImVec2(0, -footer_height_to_reserve), false, ImGuiWindowFlags_HorizontalScrollbar))
    {
        if (ImGui::BeginPopupContextWindow())
        {
            if (ImGui::Selectable("Clear")) ClearLog();
            ImGui::EndPopup();
        }

        ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(4, 1)); // Tighten spacing
        if (copy_to_clipboard)
            ImGui::LogToClipboard();
        for (int i = 0; i < Items.Size; i++)
        {
            const char* item = Items[i];
            if (!Filter.PassFilter(item))
                continue;
            ImVec4 color;
            bool has_color = false;
            if (strstr(item, "[error]")) { color = ImVec4(1.0f, 0.4f, 0.4f, 1.0f); has_color = true; }
            else if (strncmp(item, "# ", 2) == 0) { color = ImVec4(1.0f, 0.8f, 0.6f, 1.0f); has_color = true; }
            if (has_color)
                ImGui::PushStyleColor(ImGuiCol_Text, color);
            ImGui::TextUnformatted(item);
            if (has_color)
                ImGui::PopStyleColor();
        }
        if (copy_to_clipboard)
            ImGui::LogFinish();
        if (ScrollToBottom || (AutoScroll && ImGui::GetScrollY() >= ImGui::GetScrollMaxY()))
            ImGui::SetScrollHereY(1.0f);
        ScrollToBottom = false;

        ImGui::PopStyleVar();
    }
    ImGui::EndChild();
    ImGui::Separator();

    // Command-line
    bool reclaim_focus = false;
    ImGuiInputTextFlags input_text_flags = ImGuiInputTextFlags_EnterReturnsTrue | ImGuiInputTextFlags_EscapeClearsAll | ImGuiInputTextFlags_CallbackCompletion | ImGuiInputTextFlags_CallbackHistory;
    if (ImGui::InputText("Input", InputBuf, IM_ARRAYSIZE(InputBuf), input_text_flags, &TextEditCallbackStub, (void*)this))
    {
        char* s = InputBuf;
        Strtrim(s);
        if (s[0])
            ExecCommand(s);
        strcpy(s, "");
        reclaim_focus = true;
    }

    // Auto-focus on window apparition
    ImGui::SetItemDefaultFocus();
    if (reclaim_focus)
        ImGui::SetKeyboardFocusHere(-1); // Auto focus previous widget

    ImGui::End();
}

void Console::ShowDebugConsole(bool* p_open) {
    StartDebugConsole();
    Draw("Console", p_open)
}

//A.h

#pragma once
#include "imgui/imgui.h"
#include "imgui/imgui_impl_dx11.h"
#include "imgui/imgui_impl_win32.h"

class Console {
public:
	static void ShowDebugConsole();
	static void ClearLog();
	static void AddLog(const char* fmt, ...) IM_FMTARGS(2);
	static void Draw(const char* title, bool* p_open);
	static void ExecCommand(const char* command_line);
	static int TextEditCallbackStub(ImGuiInputTextCallbackData* data);
	static int TextEditCallback(ImGuiInputTextCallbackData* data);

	static void StartDebugConsole();
	static void EndDebugConsole();

	// Portable helpers
	static int   Stricmp(const char* s1, const char* s2) { int d; while ((d = toupper(*s2) - toupper(*s1)) == 0 && *s1) { s1++; s2++; } return d; }
	static int   Strnicmp(const char* s1, const char* s2, int n) { int d = 0; while (n > 0 && (d = toupper(*s2) - toupper(*s1)) == 0 && *s1) { s1++; s2++; n--; } return d; }
	static char* Strdup(const char* s) { IM_ASSERT(s); size_t len = strlen(s) + 1; void* buf = malloc(len); IM_ASSERT(buf); return (char*)memcpy(buf, (const void*)s, len); }
	static void  Strtrim(char* s) { char* str_end = s + strlen(s); while (str_end > s && str_end[-1] == ' ') str_end--; *str_end = 0; }
};

And then in the main application, I'd include the A.h file and at the part for imgui, I'd do:

bool* p_open;

Console::ShowDebugConsole(p_open);

I am very new to c++ (mostly structs and imgui) so I need more practice to get it to work.

[ocornut]

I am very new to c++ (mostly structs and imgui) so I need more practice to get it to work.

This is a C++ literacy question and not a dear imgui question so I closed the Issue and moved to Discussion but you could be discussing this anywhere C++ is being discussed.

[PsychoCoffee]

Oh, that's fine.