0x07-pointers_arrays_strings

0x07. C - Even more pointers, arrays and strings

Learning objectives for this project:

• What are pointers to pointers and how to use them
• What are multidimensional arrays and how to use them
• What are the most common C standard library functions to manipulate strings

Helper Files

• _putchar.c: Provided by Holberton School

Header Files

• main.h: Contains prototypes for all functions used in this project.

File	Prototype
0-memset.c	char *_memset(char *s, char b, unsigned int n);
1-memcpy.c	char *_memcpy(char *dest, char *src, unsigned int n);
2-strchr.c	char *_strchr(char *s, char c);
3-strspn.c	unsigned int _strspn(char *s, char *accept);
4-strpbrk.c	char *_strpbrk(char *s, char *accept);
5-strstr.c	char *_strstr(char *haystack, char *needle);
7-print_chessboard.c	void print_chessboard(char (*a)[8]);
8-print_diagsums.c	void print_diagsums(int *a, int size);
9-set_string.c	void set_string(char **s, char *to);

Tasks 📃

• 0. memset

  • 0-memset.c: C function that fills the first n bytes of memory area pointed to by s with the constant byte b.
    • Returns a pointer to the filled memory area s.

• 1. memcpy

  • 1-memcpy.c: C function that copies n bytes from memory area src to memory area dest.
    • Returns a pointer to the memory area dest.

• 2. strchr

  • 2-strchr.c: C function that returns a pointer to the first occurence of the character c in the string s.
    • If the character is not found, the function returns NULL.

• 3. strspn

  • 3-strspn.c: C function that returns the number of bytes in the intitial segment of memory area s which consist only of bytes from a substring accept.

• 4. strpbrk

  • 4-strpbrk.c: C function that locates the first occurence in a string s of any of the bytes in a string accept.
    • Returns a pointer to the byte in s that matches one of the bytes in accept.
    • If no matching byte is found, the function returns NULL.

• 5. strstr

  • 5-strstr.c: C function that finds the first occurence of a substring needle in a string haystack.
    • The terminating null bytes (\0) are not compared.
    • Returns a pointer to the beginning of the located substring.
    • If the substring is not found, the function returns NULL.

• 6. Chess is mental torture

  • 7-print_chessboard.c: C function that prints the chessboard.

• 7. The line of life is a ragged diagonal between duty and desire

  • 8-print_diagsums.c: C function that prints the sum of the two diagonals of a square matrix of integers.

• 8. Double pointer, double fun

  • 9-set_string.c: C function that sets the value of a pointer to a char.

• 9. My primary goal of hacking was the intellectual curiosity, the seduction of adventure

  • 101-crackme_password: File containing the password for the crackme2 executable.