Question

How to sort array of strings using function pointer for sort order in C

Answer 1

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

int ascending_compare(char* p1, char* p2) {
    return strcmp(p1, p2);
}

int descending_compare(char* p1, char* p2) {
    return strcmp(p2, p1);
}

void sort(char* p[], int size, int sort_type) {
    int (*compare) (char* s1, char* s2);

    compare = (sort_type) ? ascending_compare : descending_compare;

    for (int i = 1; i < size; i++) {
        for (int j = 0; j < size - 1; j++) {
            if (compare(p[j], p[j + 1]) > 0) {
                char* pstring = p[j];
                p[j] = p[j + 1];
                p[j + 1] = pstring;
            }
        }
    }
}

int main(void)
{
    char* array[] = { "java",
                      "c++",
                      "c#",
                      "python",
                      "c" };

    int size = sizeof(array) / sizeof(array[0]);

    sort(array, size, 1); // ascending order
    for (int i = 0; i < size; i++)
        puts(array[i]);
    
    printf("\n");

    sort(array, size, 0); // descending order
    for (int i = 0; i < size; i++)
        puts(array[i]);

    return 0;
}





/*
run:

c
c#
c++
java
python

python
java
c++
c#
c

*/

 

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