0x10-variadic_functions

0x10. C - Variadic functions

Learning objectives for this project:

• What are variadic functions
• How to use va_start, va_arg and va_end macros
• Why and how to use the const type qualifier

Tasks 📃

• 0. Beauty is variable, ugliness is constant

  • 0-sum_them_all.c: C program that returns the sum of all its parameters.
    • Prototype: int sum_them_all(const unsigned int n, ...);
    • If n == 0, return 0

• 1. To be is to be the value of a variable

  • 1-print_numbers.c: C program 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

• 2. One woman's constant is another woman's variable

  • 2-print_strings.c: C program 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

• 3. To be is a to be the value of a variable

  • 3-print_all.c: C 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 char should be ignored
      • see example
    • 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