Selection Sort Program

Complexity and no. of swaps required

Recursive solution

<syntaxhighlight lang="c" name="selectionsort_rec">

1. include <stdio.h>

void selection_sort(int *a, int n) {

       if(n == 1)
               return;
       int big = 0, i;
       for(i = 1; i < n; i++)
               if(a[i] > a[big])
                       big = i;
  
       /*swap a[n-1] and a[big]*/
       int temp = a[n-1];
       a[n-1] = a[big];
       a[big] = temp;
       selection_sort(a, n-1);

}

int main() {

       int a[100], i, n;
       printf("Enter n:");
       scanf("%d", &n);
       printf("Enter numbers: ");
       for(i = 0; i < n; i++)
               scanf("%d", &a[i]);
       selection_sort(a, n);
       printf("Printing sorted:\n");
       for(i = 0; i < n; i++)
               printf("%d ", a[i]);
       return 0;

}

</syntaxhighlight>

Non-Recursive solution

<syntaxhighlight lang="c" name="selectionsort_rec">

1. include <stdio.h>

void selection_sort(int *a, int n) {

       int big, i, j;
       for(i = 0; i < n; i++)
       {
               big = 0;
               for(j = 1; j < n-i; j++)
                       if(a[j] > a[big])
                               big = j;

               /*swap a[n-1] and a[big]*/
               int temp = a[n-i-1];
               a[n-i-1] = a[big];
               a[big] = temp;
       }

}

int main() {

       int a[100], i, n;
       printf("Enter n:");
       scanf("%d", &n);
       printf("Enter numbers: ");
       for(i = 0; i < n; i++)
               scanf("%d", &a[i]);
       selection_sort(a, n);
       printf("Printing sorted:\n");
       for(i = 0; i < n; i++)
               printf("%d ", a[i]);
       return 0;

}

</syntaxhighlight>

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