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0x02-functions_nested_loops

README.md

0x02. C - Functions, nested loops

Resources

Read or watch:

Learning Objectives

General

  • What are nested loops and how to use them
  • What is a function and how do you use functions
  • What is the difference between a declaration and a definition of a function
  • What is a prototype
  • Scope of variables
  • What are the gcc flags -Wall -Werror -pedantic -Wextra -std=gnu89
  • What are header files and how to to use them with #include

Tasks

0. _putchar

  • Write a program that prints _putchar, followed by a new line.

Requirements:

The program should return 0

Mode: mandatory

File: 0-putchar.c

1. I sometimes suffer from insomnia. And when I can't fall asleep, I play what I call the alphabet game

  • Write a function that prints the alphabet, in lowercase, followed by a new line.

Requirements:

Prototype: void print_alphabet(void); You can only use _putchar twice in your code

Mode: mandatory

File: 1-alphabet.c

2. 10 x alphabet

  • Write a function that prints 10 times the alphabet, in lowercase, followed by a new line.

Requirements:

Prototype: void print_alphabet_x10(void); You can only use _putchar twice in your code

Mode: mandatory

File: 2-print_alphabet_x10.c

3. islower

  • Write a function that checks for lowercase character.

Requirements:

Prototype: int _islower(int c); Returns 1 if c is lowercase Returns 0 otherwise

Mode: mandatory

File: 3-islower.c

4. isalpha

  • Write a function that checks for alphabetic character.

Requirements:

Prototype: int _isalpha(int c); Returns 1 if c is a letter, lowercase or uppercase Returns 0 otherwise

Mode: mandatory

File: 4-isalpha.c

5. Sign

  • Write a function that prints the sign of a number.

Requirements:

Prototype: int print_sign(int n); Returns 1 and prints + if n is greater than zero Returns 0 and prints 0 if n is zero Returns -1 and prints - if n is less than zero

Mode: mandatory

File: 5-sign.c

6. There is no such thing as absolute value in this world. You can only estimate what a thing is worth to you

  • Write a function that computes the absolute value of an integer.

Requirements:

Prototype: int _abs(int);

Mode: mandatory

File: 6-abs.c

7. There are only 3 colors, 10 digits, and 7 notes; it's what we do with them that's important

  • Write a function that prints the last digit of a number.

Requirements:

Prototype: int print_last_digit(int); Returns the value of the last digit

Mode: mandatory

File: 7-print_last_digit.c

8. I'm federal agent Jack Bauer, and today is the longest day of my life

  • Write a function that prints every minute of the day of Jack Bauer, starting from 00:00 to 23:59.

Requirements:

Prototype: void jack_bauer(void); You can listen to this soundtrack while coding :)

Mode: mandatory

File: 8-24_hours.c

9. Learn your times table

  • Write a function that prints the 9 times table, starting with 0.

Requirements:

Prototype: void times_table(void); Format: see example

Mode: mandatory

File: 9-times_table.c

10. a + b

  • Write a function that adds two integers and returns the result.

Requirements:

Prototype: int add(int, int);

Mode: mandatory

File: 10-add.c

11. 98 Battery Street, the OG

  • Write a function that prints all natural numbers from n to 98, followed by a new line.

Requirements:

Prototype: void print_to_98(int n); Numbers must be separated by a comma, followed by a space Numbers should be printed in order The first printed number should be the number passed to your function The last printed number should be 98 You are allowed to use the standard library

Mode: mandatory

File: 11-print_to_98.c

12. The World looks like a multiplication-table, or a mathematical equation, which, turn it how you will, balances itself

  • Write a function that prints the n times table, starting with 0.

Requirements:

Prototype: void print_times_table(int n); If n is greater than 15 or less than 0 the function should not print anything Format: see example

Mode: #advanced

File: 100-times_table.c

13. Nature made the natural numbers; All else is the work of women

  • If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. Write a program that computes and prints the sum of all the multiples of 3 or 5 below 1024 (excluded), followed by a new line.

Requirements:

You are allowed to use the standard library

Mode: #advanced

File: 101-natural.c

14. In computer class, the first assignment was to write a program to print the first 100 Fibonacci numbers. Instead, I wrote a program that would steal passwords of students. My teacher gave me an A

  • Write a program that prints the first 50 Fibonacci numbers, starting with 1 and 2, followed by a new line.

Requirements:

The numbers must be separated by comma, followed by a space ,  You are allowed to use the standard library

Mode: #advanced

File: 102-fibonacci.c

15. Even Liber Abbaci

  • Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. By considering the terms in the Fibonacci sequence whose values do not exceed 4,000,000, write a program that finds and prints the sum of the even-valued terms, followed by a new line.

Requirements:

You are allowed to use the standard library

Mode: #advanced

File: 103-fibonacci.c

16. In computer class, the first assignment was to write a program to print the first 100 Fibonacci numbers. Instead, I wrote a program that would steal passwords of students. My teacher gave me an A+

  • Write a program that finds and prints the first 98 Fibonacci numbers, starting with 1 and 2, followed by a new line.

Requirements:

The numbers should be separated by comma, followed by a space , You are allowed to use the standard library You are not allowed to use any other library (You can’t use GMP etc…) You are not allowed to use long long, malloc, pointers, arrays/tables, or structures You are not allowed to hard code any Fibonacci number (except for 1 and 2)

Mode: #advanced

File: 104-fibonacci.c