chore(C): add selection sort (#399)

algorithms/C/README.md

@@ -27,6 +27,7 @@
 - [Merge Sort](sorting/merge-sort.c)
 - [Insertion Sort](sorting/insertion-sort.c)
 - [Heap Sort](sorting/heap-sort.c)
+- [Selection Sort](sorting/selection-sort.c)
 
 ## Strings
 - [Count Words](strings/count-words.c)

algorithms/C/sorting/selection-sort.c

@@ -0,0 +1,41 @@
+
+#include <stdio.h>
+ 
+void swap(int *x, int *y)
+{
+    int t = *x;
+    *x = *y;
+    *y = t;
+}
+ 
+void selectionSort(int a[], int n)
+{
+   int i, j;
+   for (i=0;i<n-1;i++){
+       for (j=i+1;j<n;j++){
+           if(a[i]>a[j]){
+               swap(&a[i], &a[j]);
+           }
+       }
+   }    
+}
+ 
+void printArray(int a[], int size)
+{
+    int i;
+    for (i=0; i < size; i++){
+        printf("%d ", a[i]);
+    }
+}
+
+int main()
+{
+    int a[] = {64, 25, 25, 12, 22, 11, 90};
+    int n = sizeof(a)/sizeof(a[0]);
+    printf("Initial array: \n");
+    printArray(a, n);
+    selectionSort(a, n);
+    printf("\nSorted array: \n");
+    printArray(a, n);
+    return 0;
+}