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Text & File Diff4 min read

What Is a Text Diff? Added, Removed, and Modified Lines Explained

Understand the concepts behind text difference calculation, Longest Common Subsequence (LCS) algorithms, and visual diff color codes.

Understanding Diff Logic

A text diff compares two blocks of text to compute the minimal set of insertions and deletions required to turn File A into File B. NotepadDrop utilizes the Longest Common Subsequence (LCS) algorithm to ensure deterministic results.

Color Codes: Added, Removed, & Modified

Added (+): Lines present in Modified text but absent in Original. Removed (-): Lines present in Original text but removed in Modified. Modified (~): Lines where content was updated between versions.

Inline Character Highlighting

Beyond line-by-line comparison, NotepadDrop performs word-level inline diffing to highlight exact character changes within modified lines, making fine edits instantly visible.

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