Step by Step solution about How to resolve the algorithm Sort an integer array step by step in the C programming language

This C program demonstrates how to sort an integer array in ascending order using the qsort() function from the standard library. A custom comparison function intcmp() is defined to compare two integers for the sorting process. Here's a detailed breakdown of the code:

1. Header Inclusions:

   • <stdlib.h>: This header includes the qsort() function, which is used for sorting the array.
   • <stdio.h>: This header includes the printf() function for displaying output.

2. **Comparison Function intcmp()**:

   • This function is defined as the comparison function for qsort(). It takes two const void * aa and const void * bb as arguments, which are type-casted to const int * a and const int * b for integer comparison.
   • *a < *b: If the value pointed to by a is less than the value pointed to by b, the function returns -1, indicating that a should come before b in the sorted order.
   • *a > *b: If the value pointed to by a is greater than the value pointed to by b, the function returns 1, indicating that a should come after b in the sorted order.
   • Otherwise, the function returns 0, indicating that a and b are equal and their order does not matter.

3. main() Function:

   • Array Declaration: int nums[5] = {2,4,3,1,2}; declares an integer array nums of size 5 and initializes it with the values {2, 4, 3, 1, 2}.
   • Sorting the Array: qsort(nums, 5, sizeof(int), intcmp); invokes the qsort() function to sort the nums array. The arguments are:
     • nums: Pointer to the array to be sorted.
     • 5: Number of elements in the array.
     • sizeof(int): Size of each element in the array.
     • intcmp: Pointer to the comparison function.
   • Printing the Result: printf("result: %d %d %d %d %d\n", nums[0], nums[1], nums[2], nums[3], nums[4]); prints the sorted array elements in ascending order.

4. Output: After running the program, it displays the sorted array elements as: result: 1 2 2 3 4.

#include <stdlib.h>  /* qsort() */
#include <stdio.h>   /* printf() */

int intcmp(const void *aa, const void *bb)
{
    const int *a = aa, *b = bb;
    return (*a < *b) ? -1 : (*a > *b);
}

int main()
{
    int nums[5] = {2,4,3,1,2};
    qsort(nums, 5, sizeof(int), intcmp);
    printf("result: %d %d %d %d %d\n",
      nums[0], nums[1], nums[2], nums[3], nums[4]);
    return 0;
}