Question

我目前正在进行脑力训练并遇到循环问题。

我遵循了this的一些建议，但我似乎无法让它发挥作用。

到目前为止，这是我的代码：

<html>
<body>
<font face="consolas">
<script>
var brPos = 0;
var k = 0;
var loop = [];
var printtape = "";
var out = "";
var i = 0;
var pointer = 0;
var tape = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0];
var source = prompt("Code").split("");
while (i<source.length+1){
    if (source[i] == "<"){
        pointer--;
    } else if (source[i] == ">"){
        pointer++;
    } else if (source[i] == "+"){
        tape[pointer]++;
    } else if (source[i] == "-"){
        tape[pointer]--;
    } else if (source[i] == ","){
        tape[pointer] = prompt("Input").charCodeAt(0);
    } else if (source[i] == "."){
        out += String.fromCharCode(tape[pointer]);
    } else if (source[i] == "["){
        loop.push(pointer);
        if (tape[pointer] == 0){
            brPos = i;
            while (k >= 0) {
                if (source[brPos] == "[") {
                    k++;
                } else if (source[brPos] == "]") {
                    k--;
                }
            }
            i = brPos;
            brPos = 0;
            loop.pop();
        }
    } else if (source[i] == "]"){
        i=loop[loop.length-1];
    }
    i++;
    for (j=0;j<tape.length;j++) {
        if (tape[j] > 255) {
            tape[j] = 0;
        } else if (tape[j] < 0) {
            tape[j] = 255;
        }
    }
    console.log(tape);
    console.log(loop);
}
printtape = "";
printtape += "|";
for (i=0;i<tape.length;i++) {
    if (tape[i]<10) {
        printtape += "00"+tape[i]+"|";
    }
    if (tape[i]>=10&&tape[i]<100) {
        printtape += "0"+tape[i]+"|";
    }
    if (tape[i]>=100) {
        printtape += tape[i]+"|";
    }
}
printtape += "<br>";
printtape += "  ";
for (i=0;i<pointer;i++) {
    printtape += "    ";
}
printtape += "^";
document.write(printtape);
alert(out);
</script>
</font>
</body>
</html>

这是令人讨厌的代码（我认为）：

} else if (source[i] == "["){
    loop.push(pointer);
    if (tape[pointer] == 0){
        brPos = i;
        while (k >= 0) {
            if (source[brPos] == "[") {
                k++;
            } else if (source[brPos] == "]") {
                k--;
            }
        }
        i = brPos;
        brPos = 0;
        loop.pop();
    }
} else if (source[i] == "]"){
    i=loop[loop.length-1];
}

当我运行带有brainf * ck循环的代码（在IE中）时，它不会结束while循环并最终崩溃，我不知道为什么。

P.S。我知道评论中有人会说<font>标记是无效的HTML，我应该使用CSS，但它有效，它比CSS更快，我真的不在乎。

Answer 1

我对Brainfuck解析没有任何了解，但是代码逻辑失败并且你得到无限循环，因为brPos是循环内的常量。您进行相同的比较并一遍又一遍地进入k++行。如果你想离开那里，brPos必须改变。

Brainfuck解释器循环问题

1 个答案: