This project is a simple C compiler that implements a lexical analyzer for a subset of the C programming language. It reads multi-line user input, categorizes tokens like keywords, identifiers, constants, operators, and punctuation, and outputs detailed token statistics.

Compiler/
│
├── codes/                  # C source files for lexical analyzer, parser, and other logic
│   ├── lex.c               # Lexical analyzer implementation
│   ├── parse.c             # Parsing logic
│   ├── run.c               # Code execution logic
│   ├── main.c              # Main entry point
│
├── examples/               # Example input files to test the compiler
│   ├── filename.txt
│   ├── countdigits.txt
│   ├── factorial.txt
│   ├── fibonacci.txt
│   ├── grades.txt
│   ├── largestof3.txt
│   ├── power.txt
│   ├── printeven.txt
│   ├── reverse.txt
│   ├── smallestof3.txt
│   ├── sum.txt
│   ├── swap.txt
│   ├── tables.txt
│   ├── array1.txt
│   ├── array2.txt
│   ├── array3.txt
│
├── obj/                    # Object files directory (Created through commands)
│
├── outputs/                # Outputs directory (Created through commands)
│
├── project report.pdf

• Keyword recognition: Identifies keywords like int, float, if, else, switch
• Identifier recognition: Supports variables starting with alphabetic characters or underscores
• Constant recognition: Identifies numeric constants, including decimals
• Operator recognition: Supports arithmetic and logical operators like +, -, *, /, ==, !=, &&, ||
• Punctuation recognition: Recognizes common punctuation such as ;, ,, {, }, (, )
• Finite State Machine (FSM): Used for efficient token detection
• Token classification: Categorizes tokens and stores them in separate lists
• Token statistics: Outputs the number of tokens for each category

• GCC or any standard C compiler
• Basic familiarity with command-line tools

Open your terminal and run the following commands in the project root:

mkdir -p obj
gcc -std=gnu11 -Wall -Werror -c codes/lex.c -o obj/lex.o 
gcc -std=gnu11 -Wall -Werror -c codes/parse.c -o obj/parse.o
gcc -std=gnu11 -Wall -Werror -c codes/run.c -o obj/run.o
gcc -std=gnu11 -Wall -Werror -c codes/main.c -o obj/main.o
gcc -o interpret obj/lex.o obj/parse.o obj/run.o obj/main.o

▶️ Running the Compiler Test the compiler using sample inputs:

./interpret examples/filename.txt
./interpret examples/countdigits.txt
./interpret examples/factorial.txt  
./interpret examples/fibonacci.txt
./interpret examples/grades.txt
./interpret examples/largestof3.txt
./interpret examples/power.txt
./interpret examples/printeven.txt
./interpret examples/reverse.txt
./interpret examples/smallestof3.txt
./interpret examples/sum.txt
./interpret examples/swap.txt
./interpret examples/tables.txt
./interpret examples/array1.txt
./interpret examples/array2.txt
./interpret examples/array3.txt

Basics of compiler design and lexical analysis

Practical implementation of tokenization and FSM in C

Understanding string manipulation, character classification, and categorizing tokens