#include <cs50.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>

int get_index(char c);
string selectionSort(string arr, int n);

int main(int argc, string argv[])
{
    string key = argv[1];
    int str_len = strlen(key);
    string sorted = selectionSort(key, str_len);

string selectionSort(string arr, int n)
{

    int i, j, min_idx;
    for (i = 0; i < n - 1; i++)
    {
        min_idx = i;
        for (j = i + 1; j < n; j++)
        {
            if (arr[j] < arr[min_idx])
            {
                min_idx = j;
            }
        }
        char x = arr[min_idx];
        arr[min_idx] = arr[i];
        arr[i] = x;
    }
    return (string) arr;
}

I’ve got this c code and the selectionSort funcyion is updating the key variable, how could I do it so the key variable remains unchanged?

I’ve tryed to make a copy of the key but it also gets changed eaven if i set it to a const.