Step by Step solution about How to resolve the algorithm Comma quibbling step by step in the C programming language

The provided C code defines a function, quib, that takes an array of strings and its size as arguments and returns a newly allocated string representing a formatted sentence combining the input strings. A detailed explanation of its functionality:

• Function Header:

  char *quib(const char **strs, size_t size)

  • It declares a function named quib that takes two arguments:
    • const char **strs: A pointer to an array of constant C strings.
    • size_t size: The size of the strs array.
  • The function returns a character pointer (char *) to the newly allocated string.

• Variable Declarations:

  • size_t len: Stores the length of the resulting string.
  • size_t i: Loop variable.

• Calculating the Resulting String Length:

  • It initializes len to 3, which accounts for the opening and closing curly braces ({}) and a space after the opening brace.
  • If size is greater than 1, it adds 2 * size + 1 to len. This accounts for the commas and the word "and" between the strings.
  • Then, it iterates through the strs array and adds the length of each string to len.

• Allocating Memory for the Resulting String:

  • It allocates memory for the resulting string using malloc(len * sizeof(*s)). *s represents the type of s, which is char.
  • If memory allocation fails, it prints an error message and exits the program with EXIT_FAILURE.

• Formatting the Resulting String:

  • It initializes the resulting string s with an opening curly brace ({).
  • Depending on the size of the input array:
    • If size is 0, it leaves s empty.
    • If size is 1, it copies the single string from strs into s.
    • If size is greater than 1, it iterates through the strs array and concatenates each string into s. It adds commas and "and" as necessary between the strings.
  • Finally, it concatenates a closing curly brace (}) onto s.

• Returning the Result:

  • The quib function returns the newly allocated string s.

• main Function:

  • main initializes an array of constant strings test and a pointer to a character array s.
  • It iterates from i = 0 to i < 5 and repeatedly:
    • Calls quib with test and different values of i to create formatted strings.
    • Prints the formatted strings.
    • Frees the allocated memory for each formatted string.

• Output:

  • The program outputs the following formatted strings:

    {}
    {ABC}
    {ABC, DEF}
    {ABC, DEF, G}
    {ABC, DEF, G, H}
    

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

char *quib(const char **strs, size_t size)
{

    size_t len = 3 + ((size > 1) ? (2 * size + 1) : 0);
    size_t i;

    for (i = 0; i < size; i++)
        len += strlen(strs[i]);

    char *s = malloc(len * sizeof(*s));
    if (!s)
    {
        perror("Can't allocate memory!\n");
        exit(EXIT_FAILURE);
    }

    strcpy(s, "{");
    switch (size) {
        case 0:  break;
        case 1:  strcat(s, strs[0]);
                 break;
        default: for (i = 0; i < size - 1; i++)
                 {
                     strcat(s, strs[i]);
                     if (i < size - 2)
                         strcat(s, ", ");
                     else
                         strcat(s, " and ");
                 }
                 strcat(s, strs[i]);
                 break;
    }  
    strcat(s, "}");
    return s;
}

int main(void)
{
    const char *test[] = {"ABC", "DEF", "G", "H"};
    char *s;

    for (size_t i = 0; i < 5; i++)
    {
        s = quib(test, i);
        printf("%s\n", s);
        free(s);
    }
    return EXIT_SUCCESS;
}