/**
 * brainfuck_textgen.cpp
 * 
 * generates brainfuck code to print out an arbitrary string
 * usage: ./brainfuck_textgen input string goes here
 *
 * author: sangf
 * license: public domain
 */

#include <iostream>
#include <cstring>
#define ASCII_SPACE_CHAR 0x20

int main(int argc, char *argv[])
{
	if (argc > 1)
	{
		unsigned int p = 0;
		for (int i = 1; i < argc; i++)
		{
			for (unsigned int n = 0; n < strlen(argv[i]); n++)
			{
				if (p == (unsigned int) argv[i][n])
				{
					std::cout << \".\";
				}
				else if (p < (unsigned int) argv[i][n])
				{
					for (unsigned int x = 0; x < ((unsigned int) argv[i][n]) - p; x++)
					{
						std::cout << \"+\";
					}
					p = (unsigned int) argv[i][n];
					std::cout << \".\";
				}
				else
				{
					for (unsigned int x = p; x > (unsigned int) argv[i][n]; x--)
					{
						std::cout << \"-\";
					}
					p = (unsigned int) argv[i][n];
					std::cout << \".\";
				}
			}
			if ((i + 1) < argc)
			{
				std::cout << \">+[-]\";
				for (unsigned int x = 0; x < ASCII_SPACE_CHAR; x++)
				{
					std::cout << \"+\";
				}
				std::cout << \".<\";
			}
		}
	}
	return 0;
}

brainfuck_textgen.exe Hello world! >> bf.txt

Hello world!