Added .gitignore and implemented quicksort in C

.gitignore

@@ -0,0 +1,2 @@
+*.out
+.vscode

9_quick_sort/quick_sort.c

@@ -0,0 +1,54 @@
+#include<stdio.h>
+
+void swap(int* a, int* b) {
+    int t = *a;
+    *a = *b;
+    *b = t;
+}
+
+int divide (int data[], int left, int right) {
+    int pivot = data[right];
+    int i = (left - 1);
+
+    for (int j = left; j <= right- 1; j++) {
+        if (data[j] < pivot) {
+            i++;
+            swap(&data[i], &data[j]);
+        }
+    }
+    swap(&data[i + 1], &data[right]);
+    return i + 1;
+} 
+
+void quicksort(int data[], int left, int right) {
+    if (left < right) {
+        int index = divide(data, left, right);
+        quicksort(data, left, index - 1);
+        quicksort(data, index + 1, right);
+    }
+}
+
+
+int main(int argc, char* argv){
+    int test[10] = {
+        10,
+        9,
+        8,
+        7,
+        3213123,
+        5,
+        4,
+        3,
+        2,
+        1
+    };
+    int start = 0;
+    int* end = &test[(sizeof(test) / sizeof(test[0])) - 1];
+    quicksort(test, 0, (sizeof(test) / sizeof(test[0])) - 1);
+
+    for(int i = 0; i < (sizeof(test) / sizeof(test[0])); ++i){
+        printf("%i -> %i\n", i, test[i]);
+    }
+
+    return 0;
+}