我正在嘗試在 C 中實現我自己的 strpbrk function

Question

function 應該與 C 中的strpbrk function 類似地工作。 當我運行代碼時，出現分段錯誤。 我做了一個橡皮鴨調試，但無法找出代碼的任何問題。 我在 WSL 上使用 gcc 編譯器。 main.h header 文件包含 function 聲明char *_strpbrk(char *s, char *accept) 。 請問我錯過了什么？

#include "main.h"

/**
 * _strpbrk - searches the string s for any of a set of bytes
 *
 * @s: String to be searched
 * @accept: Substring of bytes to search for
 * Return: Return a pointer to the byte in s that matches one of the bytes in
 * accept, or NULL if no such byte is found
 */

char *_strpbrk(char *s, char *accept)
{
    int i, j, check = 0, position = 0;

    i = 0;
    while (*(s + i) != '\0')
    {
        for (j = 0; *(accept + j) != '\0'; j++) /* Check if character of s in focus is a character in accept. Break out of the for loop if true*/
        {
            if (*(s + i) == *(accept + j))
            {
                check = 1;
                position = i;
                break;
            }
        }

        if (check == 1) /* check if the character of s in focus was found to be in accept. Break out of the while loop if true */
        {
            break;
        }
        i++;
    }

    if (position == 0) /* Check for return value. Return null if whole string traversed*/
    {
        return ('\0');
    }
    else
    {
        return (s + position);
    }
}

忘了提到gcc標志-Wall -pedantic -Werror -Wextra -std=gnu89在編譯期間使用。

Answer 1

1. 不要使用_作為前綴。
2. 此任務顯示了使用這些功能的有用性

char *mystrchr(const char *str, const char c)
{
    while(*str)
    {
        if(*str == c) return (char *)str;
        str++;
    }
    return NULL;
}

char *mystrbrk(const char *str, const char *brk)
{
    while(*str)
    {
        if(mystrchr(brk, *str)) return (char *)str;
        str++;
    }
    return NULL;
}

現在你的代碼：

return ('\0');

這不是返回指針。 你很幸運，因為'\0'將轉換為指針 NULL。 基本上，當你想太多事情時，很難分析。

Answer 2

#include "main.h"

/**
 * _strpbrk - searches the string s for any of a set of bytes
 *
 * @s: String to be searched
 * @accept: Substring of bytes to search for
 * Return: Return a pointer to the byte in s that matches one of the bytes in
 * accept, or NULL if no such byte is found
 */

char *_strpbrk(char *s, char *accept)
{
    int i, j, check = 0, position = 0;

    i = 0;
    while (*(s + i) != '\0')
    {
        for (j = 0; *(accept + j) != '\0'; j++) /* Check if character of s in focus is a character in accept. Break out of the for loop if true*/
        {
            if (*(s + i) == *(accept + j))
            {
                check = 1;
                position = i;
                break;
            }
        }

        if (check == 1) /* check if the character of s in focus was found to be in accept. Break out of the while loop if true */
        {
            break;
        }
        i++;
    }

    if (position == 0) /* Check for return value. Return null if whole string traversed*/
    {
        return ('\0');
    }
    else
    {
        return (s + position);
    }
}