#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

int main(int argc, char **argv)
{
	if (argc != 2) {
		fprintf(stderr, "Usage: %s file.bf\n", argv[0]); 
		exit(EXIT_FAILURE);
	}

	FILE *fp = fopen(argv[1], "r");
	fseek(fp, 0, SEEK_END);
	size_t program_size = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	char program[program_size + 1];
	program[program_size] = 0;

	fread(program, sizeof(uint8_t), program_size, fp);

	fclose(fp);

	size_t dp = 0;
	size_t pc = 0;
	uint8_t mem[3000] = { 0 };

	while (pc < program_size) {
		switch (program[pc]) {
			case '>': {
				dp++;
				break;
			}
			case '<': {
				dp--;
				break;
			}
			case '+': {
				mem[dp]++;
				break;
			}
			case '-': {
				mem[dp]--;
				break;
			}
			case ',': {
				mem[dp] = getchar();
				break;
			}
			case '.': {
				putchar(mem[dp]);
				break;
			}
			case '[': {
				if (mem[dp] == 0) {
					size_t l = 1;
					while (l) {
						switch (program[++pc]) {
							case '[': {
								l++;
								break;
							}
							case ']': {
								l--;
								break;
							}
						}
					}
				}
				break;
			}
			case ']': {
				if (mem[dp] != 0) {
					size_t l = 1;
					while (l) {
						switch (program[--pc]) {
							case ']': { l++;
								break;
							}
							case '[': {
								l--;
								break;
							}
						}
					}
				}
				break;
			}
		}
		pc++;
	}

	return EXIT_SUCCESS;
}