0x10-variadic_functions

0x10. C - Variadic functions

Resource

• stdarg.h
• Variadic Functions
• Const Keyword

Tasks

• All *-main.c files will be located in the main directory.

0. Beauty is variable, ugliness is constant : A function that returns the sum of all its parameters.
   • Prototype: int sum_them_all(const unsigned int n, ...);
   • If n == 0, return 0.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 main/0-main.c 0-sum_them_all.c -o a
1. To be is to be the value of a variable : A function that prints numbers, followed by a new line.
   • Prototype: void print_numbers(const char *separator, const unsigned int n, ...);
   • Where separator is the string to be printed between numbers.
   • and n is the number of integers passed to the function.
   • You are allowed to use printf
   • If separator is NULL, don't print it.
   • Print a new line at the end of your function.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 main/1-main.c 1-print_numbers.c -o b
2. One woman's constant is another woman's variable : A function that prints strings, followed by a new line.
   • Prototype: void print_strings(const char *separator, const unsigned int n, ...);
   • Where separator is the string to be printed between the strings.
   • and n is the number of strings passed to the function.
   • You are allowed to use printf
   • If separator is NULL, don't print it.
   • If one of the string is NULL, print (nil) instead.
   • Print a new line at the end of your function.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 main/2-main.c 2-print_strings.c -o c
3. To be is a to be the value of a variable : A function that prints anything.
   • Prototype: void print_all(const char * const format, ...);
   • Where format is a list of types of arguments passed to the function.
     • c : char
     • i : integer
     • f : float
     • s : char * (if the string is NULL, print (nil) instead
     • Any other command should be ignored.
   • You are not allowed to use for, goto, ternary operator, else, do .. while
   • You can use a maximum of
     • 2 while loops
     • 2 if
   • You can declare a maximum of 9 variables.
   • You are allowed to use printf
   • Print a new line at the end of your function.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 main/3-main.c 3-print_all.c -o d
4. Real programmers can write assembly code in any language : Write a 64-bit program in asembly that prints Hello, Holberton, followed by a new line.
   • You are only allowed to use the system call write (use int or syscall, not a call)
   • Your program will be compiled using nasm and gcc (as follows) : nasm -f elf64 100-hello_holberton.asm && gcc -no-pie -std=gnu89 100-hello_holberton.o -o hello