Mini C++ Static Analyzer

A compiler-design project written in C++ that simulates core phases of a compiler frontend and performs static analysis on C++ source code — detecting lexical, syntactic, semantic, and basic runtime issues before execution.

Built as part of a Compiler Design course project.

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Features

Phase	What it catches
Lexical Analysis	Invalid characters, unterminated string/char literals
Syntax Analysis	Mismatched brackets {} () [], missing semicolons
Semantic Analysis	Undeclared variables, redeclarations, type mismatches
Runtime Checks	Division by zero, array index out-of-bounds
Warnings	Potentially unsafe array accesses

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Build & Run

Requirements: Any C++11-compatible compiler (g++, clang++)

g++ -std=c++11 -o analyzer main.cpp
./analyzer

Enter C++ code line by line. Type END on a new line to finish input and trigger analysis.

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Sample Session

Input:

int main() {
    int x;
    x = "hello";
    int arr[3];
    arr[5] = 1;
    int y = z + 1;
    float a = 10 / 0;
END

Output:

==== Semantic Errors ====
Line 3: Type mismatch: cannot assign 'string' to 'int'
  >> x = "hello";
     ^
Line 6: Use of undeclared variable 'z'
  >> int y = z + 1;
     ^

==== Runtime Errors ====
Line 7: Division by zero
  >> float a = 10 / 0;
               ^

==== Warnings ====
Line 5: Array index out-of-bounds for 'arr'
  >> arr[5] = 1;
     ^

==== Summary ====
Total Errors: 3
Total Warnings: 1

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How It Works

Input Code
    │
    ▼
┌─────────┐     Tokens (keyword, identifier,
│  Lexer  │ ──► number, operator, separator,
└─────────┘     string/char literal, invalid)
    │
    ▼
┌────────────────────────┐
│  Parser + Semantic     │  ──► Symbol Table (type, scope,
│  Analyzer              │       initialized, size)
└────────────────────────┘
    │
    ▼
┌─────────────────┐
│  Error Reporter │ ──► Categorized issues with line/column
└─────────────────┘

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Project Structure

mini-cpp-static-analyzer/
├── main.cpp       # Lexer, parser, semantic analyzer, error reporter
└── README.md

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Known Limitations

• Single-file input only (no multi-file or #include expansion)
• No function scope isolation — all variables share one symbol table
• Type inference is literal-only; expressions like x + y are not fully type-checked
• Control flow analysis (unreachable code, uninitialized use paths) not implemented
• Semicolon detection is line-based, not token-based — may produce false positives on multi-line expressions

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Technologies

• C++11
• STL: stack, map, vector, set

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Author

Asliraf Samaylan, Compiler Lab Course, Dept of CSE, IIUC