A simple, not completly working Brain F**ck compiler on C++ | When did I learn C++???

brainfuck.cpp

#include <fstream>
#include <iostream>

#define SOURCE_SIZE 10000
#define MEMORY_SIZE 30000

using std::cout;
using std::endl;

void bf_execute(char *src, int *mem, int loop) {
  while (*src) {
    switch (*src) {
    case '>':
      mem++;
      break;
    case '<':
      mem--;
      break;
    case '+':
      ++*mem;
      break;
    case '-':
      --*mem;
      break;
    case '.':
      putc(*mem, stdout);
      break;
    case ',':
      *mem = getc(stdin);
      break;

    case '[':

      if (!*mem) {
        loop = 1;
        while (loop) {
          src++;

          if (*src == '[')
            loop++;
          if (*src == ']')
            loop--;
        }
      }

      break;

    case ']':

      loop = 1;
      while (loop) {
        src--;

        if (*src == '[')
          loop--;
        if (*src == ']')
          loop++;
      }

      src--;

      break;
    }

    src++;
  }
}

int main(int argc, char *argv[]) {
  if (argc == 1) {
    cout << "ERROR: No arguments passed. \n compilation terminated." << endl;
    return 1;
  }

  FILE *file = fopen(argv[1], "r");

  if (errno) {
    cout << "File " << argv[1] << "does not exist!" << endl;
    return 1;
  }

  int memory[MEMORY_SIZE];
  char source[SOURCE_SIZE];

  fread(source, 1, SOURCE_SIZE, file);

  fclose(file);

  bf_execute(source, memory, 0);

  return 0;
}