History and Memory

Windows Calculator provides powerful history tracking and memory storage features to help you keep track of calculations and reuse values.

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Overview

History and Memory are two distinct but related features that help you manage calculations:

• History - Automatically tracks all your calculations
• Memory - Manually store values for later use

Both features are available in Standard and Scientific calculator modes. Source Reference: src/Calculator/Views/Calculator.xaml.cs:178-190

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History Features

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History Display

Each history item shows:

• Expression - The original calculation (e.g., “5 + 3”)
• Result - The calculated answer
• Timestamp - When the calculation was performed (in session)

History items are displayed in reverse chronological order (newest first). Source Reference: src/CalcViewModel/HistoryViewModel.h:25-38

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Accessing History

History can be accessed in two ways:

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Flyout Panel (Compact View)

• Click the History button
• History appears as an overlay
• Doesn’t interfere with calculator layout
• Available when window is narrow

Source Reference: src/Calculator/Views/Calculator.xaml.cs:704-721

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Docked Panel (Wide View)

• History panel docked to the side
• Visible alongside calculator
• Automatically shown in wide windows
• Can be switched with Memory panel

Source Reference: src/Calculator/Views/Calculator.xaml.cs:342-361

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History Operations

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Reuse a Calculation

1. Click any history item
2. The expression loads into the calculator
3. Result is recalculated
4. Continue calculating from that point

Source Reference: src/Calculator/Views/Calculator.xaml.cs:696-702

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Delete History Items

• Delete individual items with the delete button
• Clear all history with “Clear history” button
• Confirmation for clear all operation

Source Reference: src/CalcViewModel/HistoryViewModel.h:44-45

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History Management

History is managed intelligently:

• Persistent - History is saved between sessions
• Mode-specific - Each calculator mode has its own history
• Reload on mode change - History reloads when switching modes
• Maximum size limit - Prevents unlimited growth

Source Reference: src/CalcViewModel/HistoryViewModel.h:52

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Memory Features

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Memory Operations

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Store (MS)

Store the current display value to memory:

• Creates a new memory slot
• Value appears in memory list
• Multiple values can be stored

Source Reference: src/Calculator/Views/Calculator.xaml.cs:307-340

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Recall (MR)

Load a memory value to the display:

• Click any memory item to recall it
• Value loads into calculator
• Memory value remains stored

Source Reference: src/Calculator/Views/Calculator.xaml.cs:313-319

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Memory Add (M+)

Add current display to a memory value:

1. Select a memory item
2. Click M+ or use context menu
3. Current value is added to stored value
4. Memory updates with new sum

Source Reference: src/Calculator/Views/Memory.xaml.cs:69-76

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Memory Subtract (M-)

Subtract current display from a memory value:

1. Select a memory item
2. Click M- or use context menu
3. Current value is subtracted from stored value
4. Memory updates with new difference

Source Reference: src/Calculator/Views/Memory.xaml.cs:78-85

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Clear Memory (MC)

Remove memory values:

• Clear individual - Right-click and select “Clear”
• Clear all - Click MC button to clear all memory

Source Reference: src/Calculator/Views/Memory.xaml.cs:60-67

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Memory Display

Memory panel shows:

• Value - The stored number
• Position - Memory slot number (M1, M2, etc.)
• Context menu - Right-click for operations

Memory values are displayed in order of creation (oldest first). Source Reference: src/Calculator/Views/Memory.xaml.cs:48-58

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Memory Context Menu

Right-click any memory item to:

• M+ - Add current value
• M- - Subtract current value
• Clear - Remove this memory slot

Source Reference: src/Calculator/Views/Memory.xaml.cs:60-91

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Panel Management

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Dual Panel View (Wide Windows)

When window is wide enough:

• History and Memory both available in tabbed panel
• Switch between tabs with pivot control
• Panel docked to right side of calculator
• Tab selection persists when switching modes

Source Reference: src/Calculator/Views/Calculator.xaml.cs:322-340

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Flyout View (Narrow Windows)

When window is narrow:

• Separate flyout buttons for History and Memory
• Clicking button opens overlay panel
• Panel height matches calculator numpad
• Close by clicking outside or hide button

Source Reference: src/Calculator/Views/Calculator.xaml.cs:723-740

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Programmer Mode Differences

Source Reference: src/Calculator/Views/Calculator.xaml.cs:398-417

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Keyboard Shortcuts

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Memory Shortcuts

• Ctrl+M - Memory Store (MS)
• Ctrl+R - Memory Recall (MR)
• Ctrl+P - Memory Add (M+)
• Ctrl+Q - Memory Subtract (M-)
• Ctrl+L - Clear Memory (MC)

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History Shortcuts

• Ctrl+H - Open/close History panel
• Up/Down arrows - Navigate history items
• Enter - Select history item
• Delete - Remove selected history item

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Accessibility

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Screen Reader Support

• Descriptive automation names for all buttons
• Live region announcements for changes
• “History cleared” announcement when clearing
• “Memory cleared” announcement for memory operations

Source Reference: src/CalcViewModel/HistoryViewModel.h:31

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Automation Names

Buttons announce their state:

• “Open History” / “Close History”
• “Open Memory” / “Close Memory”
• “History - Empty” when no history
• “Memory - Empty” when no memory

Source Reference: src/Calculator/Views/Calculator.xaml.cs:265-276

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Panel Descriptions

• History & Memory Lists - Dual panel automation name
• Memory List - Programmer mode panel name
• Updates based on current mode

Source Reference: src/Calculator/Views/Calculator.xaml.cs:507-513

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Visual States

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Memory Button States

• Enabled - When memory has values
• Disabled - When memory is empty
• MR and MC buttons disable when no memory

Source Reference: src/Calculator/Views/Calculator.xaml.cs:307-321

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History Button States

• Always enabled (even when empty)
• Shows count of history items
• Visual indicator when history panel is open

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Error State

When calculator is in error state:

• Memory and History panels reflect error visually
• Operations are disabled until error is cleared
• Visual state propagates to panels

Source Reference: src/Calculator/Views/Calculator.xaml.cs:448-459

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Data Persistence

Both History and Memory data persist:

• Between sessions - Data saved when closing calculator
• Per mode - Each mode maintains separate history
• Shared memory - Memory is shared between Standard/Scientific
• Cleared on mode switch - Programmer mode has separate memory

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Always-On-Top Mode

Source Reference: src/Calculator/Views/Calculator.xaml.cs:425-446

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Related Features

• Standard Calculator - Basic calculator with memory
• Scientific Calculator - Advanced calculator with memory
• Programmer Calculator - Memory-only panel