Brainfuck interpreter

main.go

/* Brainfuck is an esoteric programming language created in 1993 by Urban Müller.
Except for its two I/O commands, Brainfuck is a minor variation of the formal programming language P′′ 
created by Corrado Böhm in 1964, which in turn is explicitly based on the Turing machine. 
In fact, using six symbols equivalent to the respective Brainfuck commands +, -, <, >, [, ], 
Böhm provided an explicit program for each of the basic functions that together serve to compute any computable function. 
*/
package main
import ("fmt",	"io/ioutil")

func main() {
	code, err := ioutil.ReadFile("input.txt")
	if err != nil {
		panic(err)
	}

	tape := make([]byte, 30000)
	pointer := 0
	output := ""

	for i := 0; i < len(code); i++ {
		command := code[i]

		switch command {
		case '>':
			pointer++
		case '<':
			pointer--
		case '+':
			tape[pointer]++
		case '-':
			tape[pointer]--
		case '.':
			output += string(tape[pointer])
		case ',':
			fmt.Scanf("%c", &tape[pointer])
		case '[':
			if tape[pointer] == 0 {
				loop_depth := 1
				for loop_depth > 0 {
					i++
					if code[i] == '[' {
						loop_depth++
					} else if code[i] == ']' {
						loop_depth--
					}
				}
			}
		case ']':
			if tape[pointer] != 0 {
				loop_depth := 1
				for loop_depth > 0 {
					i--
					if code[i] == '[' {
						loop_depth--
					} else if code[i] == ']' {
						loop_depth++
					}
				}
			}
		}
	}

	fmt.Println(output)
}

Note that this implementation assumes that the Brainfuck code in the input.txt file is valid and doesn't contain any syntax errors. If you want to add error checking, you can modify the code to check for mismatched loop brackets, invalid characters, etc.