Implement a Stack-Based VM Interpreter

Implement a complete stack-based VM interpreter in C.

Requirements:

• Define Opcode enum for PUSH, ADD, SUB, MUL, DIV, NEG, PRINT, HALT
• Implement a VM struct with bytecode array, program counter, operand stack, and stack pointer
• Implement push() and pop() operations with stack overflow/underflow checks
• Implement run() with the fetch-decode-execute loop
• Handle each opcode in a switch statement
• Support integer division
• Print the VM state (stack contents) after each instruction when a DEBUG flag is set
• Write a main() that encodes and runs a sample program: (10 + 20) * 3 - 5
• Print the final result
• Show the interpreter loop executing step by step

Test:

• Show the interpreter loop running
• Show PUSH operations placing values on the stack
• Show ADD combining two values
• Show the final computed result