可打印的putChar整数？ [英] Can putchar print an integer?

问题描述

我如何打印与的putchar 的帮助下一个整数而已。我想这样做，而无需使用外部存储。结果
这个问题在去年提出了采访。

How can i print an integer with the help of putchar only. i want to do it without using external storage.
This question was asked in a interview last year.

推荐答案

当面对上接受记者采访时含糊的要求，这是一个好主意，当然preSS你的假设。

When faced with vague requirements on an interview, it's a good idea to express your assumptions.

我将需要大约只能够使用的putchar 意味着它是唯一的库函数允许我叫的要求。我还认为，没有外部存储的意思，我可以没有明确创建一个缓冲区。如果面试官跟我的假设同意，我会继续进行：

I would take the requirement about only being able to use putchar to mean that it is the only library function I am allowed to call. I would furthermore assume that "no external storage" meant that I could not explicitly create a buffer. If the interviewer agreed with my assumptions, I would proceed with:

void pr_int(int n) {
    if (n < 0) {
        putchar('-');
        n = -n;
    }
    if (n / 10 != 0)
        pr_int(n / 10);
    putchar((n % 10) + '0');
}

如果面试官接着评论说， N = -n; 将失败的 INT_MIN ，如下所述，然后我将它改写为：

If the interviewer then commented that n = -n; would fail for INT_MIN, as noted below, then I would rewrite it as:

void pr_uint(unsigned int n) {
    if (n / 10 != 0)
        pr_uint(n / 10);
    putchar((n % 10) + '0');
}

void pr_int(int n) {
    if (n < 0) {
        putchar('-');
        n = -n;
    }
    pr_uint((unsigned int) n);
}

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