0x02-functions_nested_loops

Project

0x02. C - Functions, nested loops

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Table of Contents

• Author Details
• Project Description
• Tasks
  • 0. _putchar
  • 1. I sometimes suffer from insomnia. And when I can't fall asleep, I play what I call the alphabet game
  • 2. 10 x alphabet
  • 3. islower
  • 4. isalpha
  • 5. Sign
  • 6. There is no such thing as absolute value in this world. You can only estimate what a thing is worth to you
  • 7. There are only 3 colors, 10 digits, and 7 notes; it's what we do with them that's important
  • 8. I'm federal agent Jack Bauer, and today is the longest day of my life
  • 9. Learn your times table
  • 10. a + b
  • 11. 98 Battery Street, the OG
  • 12. The World looks like a multiplication-table, or a mathematical equation, which, turn it how you will, balances itself
  • 13. Nature made the natural numbers; All else is the work of women
  • 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
  • 15. Even Liber Abbaci
  • 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+
  • !!. Bonus - personal explainer code of task 16

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Author Details

• Dean Robin Otsyeno - [email protected]

Project Description

• Allowed editors: vi, vim, emacs
• All your files will be compiled on Ubuntu 20.04 LTS using gcc, using the options -Wall -Werror -Wextra -pedantic -std=gnu89
• All your files should end with a new line
• A README.md file, at the root of the folder of the project is mandatory
• Your code should use the Betty style. It will be checked using betty-style.pl and betty-doc.pl
• You are not allowed to use global variables
• No more than 5 functions per file
• You are not allowed to use the standard library. Any use of functions like printf, puts, etc… is forbidden
• You are allowed to use _putchar
• You don’t have to push _putchar.c, we will use our file. If you do it won’t be taken into account
• In the following examples, the main.c files are shown as examples. You can use them to test your functions, but you don’t have to push them to your repo (if you do we won’t take them into account). We will use our own main.c files at compilation. Our main.c files might be different from the one shown in the examples
• The prototypes of all your functions and the prototype of the function _putchar should be included in your header file called main.h
• Don’t forget to push your header file

Tasks

0

Table of Contents

0. _putchar

• Write a program that prints _putchar, followed by a new line.
  • The program should return 0

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 0-putchar.c

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1

Table of Contents

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

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 1-alphabet.c
  • Example file: 1-main.c

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2

Table of Contents

2. 10 x alphabet

• Write a function that prints 10 times the alphabet, in lowercase, followed by a new line.
  • Prototype: void print_alphabet_x10(void);
  • You can only use _putchar twice in your code

  julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 2-main.c 2-print_alphabet_x10.c -o 2-alphabet_x10
  julien@ubuntu:~/0x02$ ./2-alphabet_x10 
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  abcdefghijklmnopqrstuvwxyz
  

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 2-print_alphabet_x10.c
  • Example file: 2-main.c

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3

Table of Contents

3. islower

• Write a function that checks for lowercase character.
  • Prototype: int _islower(int c);
  • Returns 1 if c is lowercase
  • Returns 0 otherwise
• FYI: The standard library provides a similar function: islower. Run man islower to learn more.

julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 3-main.c 3-islower.c -o 3-islower
julien@ubuntu:~/0x02$ ./3-islower
011 

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 3-islower.c
  • Example file: 3-main.c

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4

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4. isalpha

• Write a function that checks for alphabetic character.

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

• FYI: The standard library provides a similar function: isalpha. Run man isalpha to learn more.

julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 4-main.c 4-isalpha.c -o 4-isalpha
julien@ubuntu:~/0x02$ ./4-isalpha 
1110

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 4-isalpha.c
  • Example file: 4-main.c

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5

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5. Sign

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

  • 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

   julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 5-main.c 5-sign.c -o 5-sign
   julien@ubuntu:~/0x02$ ./5-sign 
   +, 1
   0, 0
   +, 1
   -, /
  

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 5-sign.c
  • Example file: 5-main.c

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6

Table of Contents

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.

  • Prototype: int _abs(int);

• FYI: The standard library provides a similar function: abs. Run man abs to learn more.

   julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 6-main.c 6-abs.c -o 6-abs
   julien@ubuntu:~/0x02$ ./6-abs
   1
   0
   1
   98
  

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 6-abs.c
  • Example file: 6-main.c

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7

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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

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

   julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 7-main.c 7-print_last_digit.c -o 7-last_digit
   julien@ubuntu:~/0x02$ ./7-last_digit
   8044
  

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 7-print_last_digit.c
  • Example file: 7-main.c

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8

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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.

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

julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 8-main.c 8-24_hours.c -o 8-24
julien@ubuntu:~/0x02$ ./8-24 | head -3
00:00
00:01
00:02
julien@ubuntu:~/0x02$ ./8-24 | tail -3
23:57
23:58
23:59

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 8-24_hours.c
  • Example file: 8-main.c

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9

Table of Contents

9. Learn your times table

• Write a function that prints the 9 times table, starting with 0.
  • Prototype: void times_table(void);
  • Format: see example

julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 9-main.c 9-times_table.c -o 9-times_table
ulien@ubuntu:~/0x02$ ./9-times_table | cat -e
0,  0,  0,  0,  0,  0,  0,  0,  0,  0$
0,  1,  2,  3,  4,  5,  6,  7,  8,  9$
0,  2,  4,  6,  8, 10, 12, 14, 16, 18$
0,  3,  6,  9, 12, 15, 18, 21, 24, 27$
0,  4,  8, 12, 16, 20, 24, 28, 32, 36$
0,  5, 10, 15, 20, 25, 30, 35, 40, 45$
0,  6, 12, 18, 24, 30, 36, 42, 48, 54$
0,  7, 14, 21, 28, 35, 42, 49, 56, 63$
0,  8, 16, 24, 32, 40, 48, 56, 64, 72$
0,  9, 18, 27, 36, 45, 54, 63, 72, 81$

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 9-times_table.c
  • Example file: 9-main.c

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10

Table of Contents

10. a + b

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

  • Prototype: int add(int, int);

julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 10-main.c 10-add.c -o 10-add
julien@ubuntu:~/0x02$ ./10-add 
98

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 10-add.c
  • Example file: 10-main.c

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11

Table of Contents

11. 98 Battery Street, the OG

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

  • 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

julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 11-main.c 11-print_to_98.c -o 11-98
julien@ubuntu:~/0x02$ ./11-98 
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98
98
111, 110, 109, 108, 107, 106, 105, 104, 103, 102, 101, 100, 99, 98
81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98
-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 11-print_to_98.c
  • Example file: 11-main.c

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12

Table of Contents

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.

  • 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

julien@ubuntu:~/0x02$ gcc -Wall -pedantic -Werror -Wextra -std=gnu89 _putchar.c 100-main.c 100-times_table.c -o 100-times_table
julien@ubuntu:~/0x02$ ./100-times_table 
0,   0,   0,   0
0,   1,   2,   3
0,   2,   4,   6
0,   3,   6,   9

0,   0,   0,   0,   0,   0
0,   1,   2,   3,   4,   5
0,   2,   4,   6,   8,  10
0,   3,   6,   9,  12,  15
0,   4,   8,  12,  16,  20
0,   5,  10,  15,  20,  25


0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0
0,   1,   2,   3,   4,   5,   6,   7,   8,   9,  10,  11,  12
0,   2,   4,   6,   8,  10,  12,  14,  16,  18,  20,  22,  24
0,   3,   6,   9,  12,  15,  18,  21,  24,  27,  30,  33,  36
0,   4,   8,  12,  16,  20,  24,  28,  32,  36,  40,  44,  48
0,   5,  10,  15,  20,  25,  30,  35,  40,  45,  50,  55,  60
0,   6,  12,  18,  24,  30,  36,  42,  48,  54,  60,  66,  72
0,   7,  14,  21,  28,  35,  42,  49,  56,  63,  70,  77,  84
0,   8,  16,  24,  32,  40,  48,  56,  64,  72,  80,  88,  96
0,   9,  18,  27,  36,  45,  54,  63,  72,  81,  90,  99, 108
0,  10,  20,  30,  40,  50,  60,  70,  80,  90, 100, 110, 120
0,  11,  22,  33,  44,  55,  66,  77,  88,  99, 110, 121, 132
0,  12,  24,  36,  48,  60,  72,  84,  96, 108, 120, 132, 144
julien@ubuntu:~/0x02$ ./100-times_table | tr ' ' . | cat -e
0,...0,...0,...0$
0,...1,...2,...3$
0,...2,...4,...6$
0,...3,...6,...9$
$
0,...0,...0,...0,...0,...0$
0,...1,...2,...3,...4,...5$
0,...2,...4,...6,...8,..10$
0,...3,...6,...9,..12,..15$
0,...4,...8,..12,..16,..20$
0,...5,..10,..15,..20,..25$
$
$
0,...0,...0,...0,...0,...0,...0,...0,...0,...0,...0,...0,...0$
0,...1,...2,...3,...4,...5,...6,...7,...8,...9,..10,..11,..12$
0,...2,...4,...6,...8,..10,..12,..14,..16,..18,..20,..22,..24$
0,...3,...6,...9,..12,..15,..18,..21,..24,..27,..30,..33,..36$
0,...4,...8,..12,..16,..20,..24,..28,..32,..36,..40,..44,..48$
0,...5,..10,..15,..20,..25,..30,..35,..40,..45,..50,..55,..60$
0,...6,..12,..18,..24,..30,..36,..42,..48,..54,..60,..66,..72$
0,...7,..14,..21,..28,..35,..42,..49,..56,..63,..70,..77,..84$
0,...8,..16,..24,..32,..40,..48,..56,..64,..72,..80,..88,..96$
0,...9,..18,..27,..36,..45,..54,..63,..72,..81,..90,..99,.108$
0,..10,..20,..30,..40,..50,..60,..70,..80,..90,.100,.110,.120$
0,..11,..22,..33,..44,..55,..66,..77,..88,..99,.110,.121,.132$
0,..12,..24,..36,..48,..60,..72,..84,..96,.108,.120,.132,.144$

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 100-times_table.c
  • Example file: 100-main.c

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13

Table of Contents

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.
  • You are allowed to use the standard library

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 101-natural.c

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14

Table of Contents

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

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 102-fibonacci.c

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15

Table of Contents

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.

  • You are allowed to use the standard library

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 103-fibonacci.c

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16

Table of Contents

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.

  • 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)

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 104-fibonacci.c
  • • Code Explainer: 104-fibonacci-explainer_d333.c

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17

Table of Contents

!!. Bonus - personal explainer code of task 16

• When you compile and ran this code, it will break down in detail how the splitting of task 16 happens, in file 104-fibonacci.c
• You can test using various number of examples, by changing basic parameters
• Running as it is will show you how the next 3 fibonacci sequences from the 92nd are gotten

• Repo
  • GitHub repository: alx-low_level_programming
  • Directory: 0x02-functions_nested_loops
  • File: 104-fibonacci-explainer_d333.c

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_{Dean Robin Otsyeno - [email protected]}