C - printf
Description
With this project we are doing a simple implimentation of the printf function that formarts and prints data on the screen.
We wrote our own printf fuction.
AUTHORS
Resources
Authorized functions and macros
- write (man 2 write)
- malloc (man 3 malloc)
- free (man 3 free)
- va_start (man 3 va_start)
- va_end (man 3 va_end)
- va_copy (man 3 va_copy)
- va_arg (man 3 va_arg)
*Compilation
Our code will be compiled this way:
*$ gcc -Wall -Werror -Wextra -pedantic -std=gnu89 .c
As a consequence, be careful not to push any c file containing a main function in the root directory of your project (you could have a test folder containing all your tests files including main functions)
Our main files will include your main header file (main.h): #include main.h You might want to look at the gcc flag -Wno-format when testing with your _printf and the standard printf.
Example of test file that you could use:
alex@ubuntu:~/c/printf$ cat main.c
#include <limits.h>
#include <stdio.h>
#include "main.h"
/**
- main - Entry point
- Return: Always 0 */
int main(void)
{
int len;
int len2;
unsigned int ui;
void *addr;
len = _printf("Let's try to printf a simple sentence.\n");
len2 = printf("Let's try to printf a simple sentence.\n");
ui = (unsigned int)INT_MAX + 1024;
addr = (void *)0x7ffe637541f0;
_printf("Length:[%d, %i]\n", len, len);
printf("Length:[%d, %i]\n", len2, len2);
_printf("Negative:[%d]\n", -762534);
printf("Negative:[%d]\n", -762534);
_printf("Unsigned:[%u]\n", ui);
printf("Unsigned:[%u]\n", ui);
_printf("Unsigned octal:[%o]\n", ui);
printf("Unsigned octal:[%o]\n", ui);
_printf("Unsigned hexadecimal:[%x, %X]\n", ui, ui);
printf("Unsigned hexadecimal:[%x, %X]\n", ui, ui);
_printf("Character:[%c]\n", 'H');
printf("Character:[%c]\n", 'H');
_printf("String:[%s]\n", "I am a string !");
printf("String:[%s]\n", "I am a string !");
_printf("Address:[%p]\n", addr);
printf("Address:[%p]\n", addr);
len = _printf("Percent:[%%]\n");
len2 = printf("Percent:[%%]\n");
_printf("Len:[%d]\n", len);
printf("Len:[%d]\n", len2);
_printf("Unknown:[%r]\n");
printf("Unknown:[%r]\n");
return (0);
}
alex@ubuntu:~/c/printf$ gcc -Wall -Wextra -Werror -pedantic -std=gnu89 -Wno-format *.c
alex@ubuntu:~/c/printf$ ./printf
Let's try to printf a simple sentence.
Let's try to printf a simple sentence.
Length:[39, 39]
Length:[39, 39]
Negative:[-762534]
Negative:[-762534]
Unsigned:[2147484671]
Unsigned:[2147484671]
Unsigned octal:[20000001777]
Unsigned octal:[20000001777]
Unsigned hexadecimal:[800003ff, 800003FF]
Unsigned hexadecimal:[800003ff, 800003FF]
Character:[H]
Character:[H]
String:[I am a string !]
String:[I am a string !]
Address:[0x7ffe637541f0]
Address:[0x7ffe637541f0]
Percent:[%]
Percent:[%]
Len:[12]
Len:[12]
Unknown:[%r]
Unknown:[%r]
alex@ubuntu:~/c/printf$
*Tasks
- I'm not going anywhere. You can print that wherever you want to. I'm here and I'm a Spur for life
Write a function that produces output according to a format.
Prototype: int _printf(const char *format, ...);
Returns: the number of characters printed (excluding the null byte used to end output to strings)
write output to stdout, the standard output stream
format is a character string. The format string is composed of zero or more directives. See man 3 printf for more detail. You need to handle the following conversion specifiers:
c
s
%
You don’t have to reproduce the buffer handling of the C library printf function
You don’t have to handle the flag characters
You don’t have to handle field width
You don’t have to handle precision
You don’t have to handle the length modifiers
- Education is when you read the fine print. Experience is what you get if you don't
Handle the following conversion specifiers:
d
i You don’t have to handle the flag characters
You don’t have to handle field width
You don’t have to handle precision
You don’t have to handle the length modifiers
- With a face like mine, I do better in print
Handle the following custom conversion specifiers:
b: the unsigned int argument is converted to binary
alex@ubuntu:~/c/printf$ cat main.c
#include "main.h"
/**
- main - Entry point
- Return: Always 0 */
int main(void)
{
_printf("%b\n", 98);
return (0);
}
alex@ubuntu:~/c/printf$ gcc -Wall -Wextra -Werror -pedantic -std=gnu89 main.c
alex@ubuntu:~/c/printf$ ./a.out
1100010
alex@ubuntu:~/c/printf$