0x0C-more_malloc_free

0x0C. C - More malloc, free

Resource

• Do I cast the result of malloc
• Read this post malloc and free it's from the concept page.

Tasks

0. Trust no one : A function that allocates memory using malloc.
   • Prototype: void *malloc_checked(unsigned int b);
   • Returns a pointer to the allocated memory.
   • If malloc fails, the malloc_checked function should cause normal process termination with a status value of 98.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 0-main.c 0-malloc_checked.c -o a
1. string_nconcat : A function that concatenates two strings.
   • Prototype: char *string_nconcat(char *s1, char *s2, unsigned int n);
   • The returned pointer shall point to a newly allocated space in memory, which contains s1, followed by the first n bytes of s2, and null terminated.
   • If the function fails, it should return NULL.
   • If n is greater or equal to the length of s2 then use the entire string s2.
   • If NULL is passed, treat it as an empty string.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 1-main.c 1-string_nconcat.c -o b
2. _calloc : A function that allocates memory for an array, using malloc.
   • Prototype: void *_calloc(unsigned int nmemb, unsigned int size);
   • The _calloc function allocates memory for an array of nmemb elements of size bytes each and returns a pointer to the allocated memory.
   • The memory is set to zero.
   • If nmemb or size is 0, then _calloc returns NULL.
   • If malloc fails, then _calloc returns NULL.
   • FYI: The standard library provides a different function: calloc. Run man calloc to learn more.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 2-main.c 2-calloc.c -o c
3. array_range : A function that creates an array of integers.
   • Prototype: int *array_range(int min, int max);
   • The array created should contain all the values from min (included) to max (included), ordered from min to max.
   • Return: the pointer to the newly created array.
   • If min > max, return NULL
   • If malloc fails, return NULL
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 3-main.c 3-array_range.c -o d
4. _realloc : A function that reallocates a memory block using malloc and free.
   • Prototype: void *_realloc(void *ptr, unsigned int old_size, unsigned int new_size);
   • Where ptr is a pointer to the memory previously allocated with a call to malloc: malloc(old_size).
   • old_size is the size, in bytes, of the allocated space for ptr.
   • and new_size is the new size, in bytes of the new memory block.
   • The contents will be copied to the newly allocated space, in the range from the start of ptr up to the minimum of the old and new sizes.
   • If new_size > old_size, the "added" memory should not be initialized.
   • If new_size == old_size do not do anything and return ptr.
   • If ptr is NULL, then call is equivalent to malloc(new_size), for all values of old_size and new_size.
   • If new_size is equal to zero, and ptr is not NULL, then the call is equivalent to free(ptr). Return NULL.
   • Don't forget to free ptr when it makes sense.
   • FYI: The standard library provides a different function: realloc. Run man realloc to learn more.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 100-main.c 100-realloc.c -o e
5. We must accept finite disappointment, but never lose infinite hope : A program that multiplies two positive numbers.
   • Usage: mul num1 num2
   • num1 and num2 will be passed in base 10.
   • Print the result, followed by a new line.
   • If the number of arguments is incorrect, print Error, followed by a new line, and exit with a status of 98.
   • num1 and num2 should only be composed of digits. If not, print Error, followed by a new line, and exit with a status of 98.
   • You are allowed to use more that 5 functions in your file.
   • You can use bc (man bc) to check your results.
   • Compile the code this way: gcc -Wall -pedantic -Werror -Wextra -std=gnu89 101-mul.c _putchar.c -o mul