diff --git a/learnc/a.exe b/learnc/a.exe
index 194a1b0..6e32960 100755
Binary files a/learnc/a.exe and b/learnc/a.exe differ
diff --git a/learnc/learnc12.c b/learnc/learnc12.c
new file mode 100755
index 0000000..7f02501
--- /dev/null
+++ b/learnc/learnc12.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main() {
+    int i, j;
+    /* TODO: define the 2D pointer variable here */
+    int **pnumbers;
+
+    /* TODO: complete the following line to allocate memory for holding three rows */
+    pnumbers = (int **) malloc(3 *sizeof(int *));
+
+    /* TODO: allocate memory for storing the individual elements in a row */
+    pnumbers[0] = (int *) malloc(1 * sizeof(int));
+    pnumbers[1] = (int *) malloc(2 * sizeof(int));
+    pnumbers[2] = (int *) malloc(3 * sizeof(int));
+
+
+    pnumbers[0][0] = 1;
+    pnumbers[1][0] = 1;
+    pnumbers[1][1] = 1;
+    pnumbers[2][0] = 1;
+    pnumbers[2][1] = 2;
+    pnumbers[2][2] = 1;
+
+    for (i = 0; i < 3; i++) {
+        for (j = 0; j <= i; j++) {
+            printf("%d", pnumbers[i][j]);
+        }
+        printf("\n");
+    }
+
+    for (i = 0; i < 3; i++) {
+        /* TODO: free memory allocated for each row */
+        free(pnumbers[i]);
+    }
+
+    /* TODO: free the top-level pointer */
+    free(pnumbers);
+
+  return 0;
+}
\ No newline at end of file
diff --git a/learnc/learnc13.c b/learnc/learnc13.c
new file mode 100755
index 0000000..3e59dd8
--- /dev/null
+++ b/learnc/learnc13.c
@@ -0,0 +1,25 @@
+#include <stdio.h>
+
+int factorial(int x);
+
+int main() {
+    /* testing code */
+    printf("0! = %i\n", factorial(0));
+    printf("1! = %i\n", factorial(1));
+    printf("3! = %i\n", factorial(3));
+    printf("5! = %i\n", factorial(5));
+}
+
+/* define your function here (don't forget to declare it) */
+int factorial(int x) {
+    
+    if (x == 0) {
+        
+        return 1;
+    } else if (x >= 1) {
+
+        return x*factorial(x-1);
+    }
+    
+    return 0;
+}
\ No newline at end of file