How to sort arrays in C language

Sort is a process of sorting data in a specific order. In C language, you can use the qsort() function to sort arrays. This function requires a comparison function to compare two elements and return the comparison result. For example, the following code demonstrates how to sort an array of integers from small to large using the int_compare() comparison function.

C language array sorting

What is the sorting?

Sort is a process of sorting data in a specific order, such as from small to large or from large to small.

How to use array sorting in C?

In C language, you can use the qsort() function to sort arrays. The function prototype is as follows:

 <code class="c">void qsort(void *base, size_t num, size_t size, int (*compar)(const void*, const void*));</code>

• base: the first address of the array to be sorted
• num: The number of elements in the array
• size: the size of each element in bytes
• Compar: Comparison function, used to compare two elements and return comparison results

Comparison function

In order to use qsort() , a comparison function needs to be provided. This function takes a pointer to two elements and returns an integer representing the result of the comparison between the two elements:

• Negative value: The first element is smaller than the second element
• Zero: Two elements are equal
• Positive value: The first element is greater than the second element

Sample code

The following example demonstrates how to sort an array of integers using qsort() :

 <code class="c">#include <stdio.h> #include <stdlib.h> int int_compare(const void *a, const void *b) { int *pa = (int*)a; int *pb = (int*)b; return *pa - *pb; } int main() { int arr[] = {3, 1, 4, 2, 5}; int n = sizeof(arr) / sizeof(arr[0]); qsort(arr, n, sizeof(int), int_compare); for (int i = 0; i </stdlib.h></stdio.h></code>

Output:

 <code>1 2 3 4 5</code>

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