0x06-pointers_arrays_strings

0x06. C - More pointers, arrays, and strings 💻🚀

This directory contains C programs that demonstrate various string and array manipulation functions. The programs cover tasks such as string concatenation, string comparison, string copying, and more.

Programs 📜

Task 0: Concatenate Strings 🧬🧬

• File: 0-strcat.c
• Prototype: char *_strcat(char *dest, char *src);
• Description: This function appends the src string to the dest string, overwriting the terminating null byte (\0) at the end of dest, and then adds a terminating null byte. It returns a pointer to the resulting string dest.

Task 1: Concatenate with Limited Bytes 🧬🧬

• File: 1-strncat.c
• Prototype: char *_strncat(char *dest, char *src, int n);
• Description: This function is similar to the _strcat function but with the added feature that it will use at most n bytes from src. If src does not contain a null byte in the first n bytes, the result will not be null-terminated.

Task 2: Copy a String 📝

• File: 2-strncpy.c
• Prototype: char *_strncpy(char *dest, char *src, int n);
• Description: This function works exactly like the strncpy function from the standard library. It copies at most n characters from the src string into the dest string. If src is shorter than n characters, the remaining characters in dest are filled with null bytes (\0).

Task 3: String Comparison 🔃

• File: 3-strcmp.c
• Prototype: int _strcmp(char *s1, char *s2);
• Description: This function compares two strings s1 and s2 and returns an integer value indicating their relationship. It returns:
  • 0 if s1 and s2 are equal,
  • a negative value if s1 is less than s2 in lexicographical order, and
  • a positive value if s1 is greater than s2 in lexicographical order.

Task 4: Reverse Array of Integers ↺

• File: 4-rev_array.c
• Prototype: void reverse_array(int *a, int n);
• Description: This function reverses the content of an array of integers. It takes an array a with n elements, and it modifies the array a in place, reversing its content.

Task 5: Convert Lowercase Letters to Uppercase 🌟🔠

• File: 5-string_toupper.c
• Prototype: char *string_toupper(char *);
• Description: This function changes all lowercase letters of a string to uppercase. It takes a string as input and returns a pointer to the resulting uppercase string.

Task 6: Capitalize Words in a String 🎩🗣️

• File: 6-cap_string.c
• Prototype: char *cap_string(char *);
• Description: This function capitalizes all words of a string. Words are separated by spaces, tabs, new lines, commas, semicolons, periods, exclamation marks, question marks, double quotes, opening parentheses, and closing parentheses. It takes a string as input and returns a pointer to the resulting string with capitalized words.

Task 7: Encode a String to "1337" 🔢🔢🔢

• File: 7-leet.c
• Prototype: char *leet(char *);
• Description: This function encodes a string into "1337" (leet speak). The encoding rules are as follows:
  • Letters 'a' and 'A' are replaced by '4'.
  • Letters 'e' and 'E' are replaced by '3'.
  • Letters 'o' and 'O' are replaced by '0'.
  • Letters 't' and 'T' are replaced by '7'.
  • Letters 'l' and 'L' are replaced by '1'.
  • Other characters are unchanged. It takes a string as input and returns a pointer to the resulting leet speak string.

Task 8: Encode a String using Rot13 🔠➡️🔡

• File: 100-rot13.c
• Prototype: char *rot13(char *);
• Description: This function encodes a string using ROT13 encryption. ROT13 is a simple letter substitution cipher where each letter in the input is shifted by 13 positions in the alphabet. It takes a string as input and returns a pointer to the resulting encrypted string.

Task 9: Print an Integer 🔢🖨️

• File: 101-print_number.c
• Prototype: void print_number(int n);
• Description: This function prints an integer n. It uses only the _putchar function to print the number.

Task 10: Add Two Numbers ➕➕

• File: 103-infinite_add.c
• Prototype: char *infinite_add(char *n1, char *n2, char *r, int size_r);
• Description: This function adds two numbers represented as strings and stores the result in a buffer r. The size of the buffer is specified by size_r. The function returns a pointer to the result string. If the result cannot be stored in the buffer due to its size, the function returns 0.

Task 11: Print Buffer 📜➡️🖨️

• File: 103-print_buffer.c
• Prototype: void print_buffer(char *b, int size);
• Description: This function prints the content of a buffer b of size size. It prints 10 bytes per line, showing the position of the first byte of the line in hexadecimal. Each line also shows the hexadecimal content (2 chars) of the buffer, 2 bytes at a time, separated by a space. If the byte is a printable character, it is printed; otherwise, a period (.) is printed. Each line ends with a new line \n. If size is 0 or less, the output is a new line only \n.

Please note that the _putchar function used in some files is a custom function used to print characters.

Enjoy coding! 🚀