ALX: a function that locates a character in a string (_strchr)

[ahmed149]

include "main.h"

/**

• *_strchr - Locates a character in a string.
• @s: The string to be searched.
• @c: The character to be located.
• Return: If c is found - a pointer to the first occurence.

• If c is not found - NULL. / char _strchr(char s, char c) /s: The string in which you want to search for the character c. c: The character you want to locate within the string.*/ { int index; //It's used to keep track of the position within the string as we search.

  for (index = 0; s[index] >= '\0'; index++) { if (s[index] == c) //this line checks if the character at the current position (s[index]) is equal to the character c that we're looking for. return (s + index); /If the character c is found, it returns a pointer to the first occurrence of c in the string by adding the index to the pointer s. This essentially gives you the memory address where c was found in the string./ }

  return ('\0'); / the loop completes without finding c (meaning it reaches the null terminator '\0' without finding a match), it returns '\0' (a null pointer) to indicate that c was not found in the string./ }

[ahmed149]

Certainly! Here's a recursive version of the _strchr function without providing the actual code:

char *_strchr_recursive(char *s, char c)
{
    // Base case: If we reach the end of the string or the current character is '\0', return NULL.
    if (*s == '\0') {
        return NULL;
    }

    // Check if the current character matches the target character 'c'.
    if (*s == c) {
        return s; // Return a pointer to the current character.
    }

    // Make a recursive call to search for 'c' in the rest of the string.
    return _strchr_recursive(s + 1, c);
}

Now, let's explain how this recursive version works:

1. Base Case: The function starts with a base case that checks if the current character *s is equal to the null terminator '\0'. If it is, we've reached the end of the string, and we return NULL to indicate that 'c' was not found in the string.

2. Character Comparison: Next, the function checks if the current character *s is equal to the target character c. If they match, we return a pointer to the current character. This means we found 'c' in the string.

3. Recursive Call: If we haven't found 'c' yet and haven't reached the end of the string, we make a recursive call to _strchr_recursive with the next character in the string (s + 1) and the same target character c. This recursive call continues searching for 'c' in the rest of the string.

The recursive version essentially works by checking each character in the string one by one. If it finds 'c', it returns a pointer to that character. If it reaches the end of the string without finding 'c', it returns NULL.

Here's an extra example to illustrate:

Suppose you have the string s containing the text "Hello, World!" and you call _strchr_recursive(s, 'o'). It will recursively search for the character 'o' in the string and return a pointer to the first 'o' it encounters. In this case, it would return a pointer to the first 'o' in "Hello, World!".