# Simple Interpreter This program is a simple interpreter for a subset of the C programming language, specifically designed to handle basic operations such as integer and string variable declarations, assignments, arithmetic operations, string concatenations, and input/output operations. The program processes the input line by line and maintains a symbol table to keep track of declared variables. ## Features - **Integer and String Declarations**: Supports the declaration of integer and string variables. - **Assignment Operations**: Handles assignments for both integer and string variables. - **Arithmetic Operations**: Supports basic arithmetic operations (`+`, `-`, `*`, `/`) on integer variables. - **String Concatenation**: Allows concatenation of string variables. - **Input and Output**: Supports `scanf` for user input and `print` for output. ## Input Syntax The interpreter recognizes the following commands: ### 1. Integer Declaration and Assignment - **Syntax**: `int = ;` or `int ;` - **Example**: ```c int a = 5; int b = a + 3; int c; ``` ### 2. String Declaration and Assignment - **Syntax**: `string = "";` or `string ;` - **Example**: ```c string s = "hello"; string t = s + " world"; string u; ``` ### 3. Arithmetic Operations - **Syntax**: ` = ;` - **Example**: ```c int x = a + b * 2; ``` ### 4. String Concatenation - **Syntax**: ` = ;` - **Example**: ```c string greeting = "hello" + " world"; ``` ### 5. Print Statement - **Syntax**: `print ;` - **Example**: ```c print a; print greeting; ``` ### 6. Scanf Statement - **Syntax**: `scanf ;` - **Example**: ```c scanf a; scanf s; ``` ### 7. Exit Command - **Syntax**: `exit` - **Description**: Terminates the interpreter. ## Error Handling The interpreter provides basic error handling, including: - **Undefined Variables**: Reports an error if a variable is used before it is declared. - **Uninitialized Variables**: Reports an error if a variable is used before it is initialized. - **Type Mismatch**: Reports an error if operations are attempted between incompatible types (e.g., adding a string and an integer). - **Division by Zero**: Reports an error if an attempt is made to divide by zero. ## Running the Program 1. Compile the program using a C compiler: ```bash gcc sample.c -o interpreter ``` 2. Run the interpreter: ```bash ./interpreter ``` 3. Start typing commands as per the syntax described above. The interpreter will continue to process commands until you type `exit`. ## Example Usage ```c >>> int a = 10; >>> int b = 20; >>> int c = a + b; >>> print c; 30 >>> string s = "Hello"; >>> string t = s + " World"; >>> print t; Hello World >>> scanf c; Enter value for c: 50 >>> print c; 50 >>> exit ``` ## Limitations - The interpreter currently supports only basic integer arithmetic and string concatenation. - No support for floating-point numbers or complex data types. - No support for control structures (e.g., loops, conditionals).