K&R，找到最长的线路，相同的代码但不起作用？

Question

我刚开始阅读 K&R，在第 32-33 页，有一段代码

finds the longest line among the inputs.

我几乎完全复制粘贴了书中给出的代码，只是添加了一些注释行以使代码对我来说更容易理解。但它不起作用。

编辑：不好意思提问。当我按下 Ctrl + Z 以终止程序时，程序似乎无法正常运行。无论我输入多少行，按多少次 Ctrl + Z，它都没有任何反应。

以下是我的代码版本：

/* Find the longest line among the giving inputs and print it */

#include <stdio.h>
#define MAXLINE 1000            /* maximum input line length */

int getLine(char line[], int maxLine);
void copy(char to[], char from[]);

int main(void) {
    int len; /* current line length */
    int max; /* maximum length seen so far */
    char line[MAXLINE]; /* current input line */
    char longest[MAXLINE]; /* longest line saved here*/

    max = 0;

    /* getLine function takes all the input from user, returns it's size and equates it to the variable len
     * Then, len is compared whether it's greater than zero because if there's no input, no need to do any calculation
     * EDGE CASE
     */
    while ((len = getLine(line, MAXLINE)) > 0)
        /* If the length of input is larger than the previous max length, set max as the new length value and copy that input */
        if (len > max) {
            max = len;
            copy(longest, line);
        }
    if (max > 0) /* there was a line, EDGE CASE */
        printf("%s", longest);

    return 0;
}

/* Read a line into s, return length.
 * Since the input length is unknown, there should be a limit */
int getLine(char s[], int lim) {
    int c, i;

    /* The loop's first condition is whether the input length is below the limit. EDGE CASE
     * If it's not, omit the rest because it would cause a BUFFER OVERFLOW. Next, take the input as long as it's not an EOF command.
     * Finally, if the input is end of line, finish the loop, don' take it.
     */
    for (i = 0; i < lim - 1 && (c = getchar()) != EOF && c != '\n'; i++)
        s[i] = c;
    if (c == '\n')
        s[i++] = c;
    s[i++] = '[=10=]'; // always put a '[=10=]' character to a string array ending, so that the compiler knows it's a string.
    return i;
}

void copy(char to[], char from[]) {
    int i = 0;

    // This loop is readily assigns all chars from the source array to the target array until it reaches the ending char.
    while ((to[i] = from[i]) != '[=10=]')
        ++i;
}

提前致谢！

Answer 1

好的，这是错误：

s[i++] = '[=10=]'; // always put a '[=10=]' character to a string array ending, so that the compiler knows it's a string.

即使没有输入（当它直接得到 EOF 时），这也会导致它终止字符串，并且由于它在 return 之前递增 i，getLine() 永远不会 return 0 因此 main() 永远不会停止。删除 ++ 修复它，用于我的简单测试。

此外，评论具有误导性，编译器什么都不知道。当代码运行s时，编译器不再存在；字符串的内存格式是让运行时代的图书馆满意所需要的，因为这是他们所期望的。

K&R，找到最长的线路，相同的代码但不起作用？

K&R, find longest line, same code but not working?

c

kernighan-and-ritchie