diff --git a/programs/C/factorial.c b/programs/C/factorial.c
new file mode 100644
index 0000000..fff5a56
--- /dev/null
+++ b/programs/C/factorial.c
@@ -0,0 +1,68 @@
+#include<stdio.h>
+int main()
+{
+    int choose = 0, n, i;
+    unsigned long long factorial = 1;
+
+   while (choose !=3){
+   factorial = 1;
+
+   printf("Type number to choose \n 1. factorial \n 2. double factorial \n 3.Exit\n  Choice: ");
+   scanf("%d", &choose);
+
+   switch(choose){
+
+   case(1):
+      printf("Enter an integer: ");
+      scanf("%d",&n);
+
+      if (n > 0){
+        for(i=1; i<=n; ++i)
+        {
+            factorial *= i;  //n! = n*(n-1)...
+        }
+      }
+      else if( n = 0){
+        factorial = 1; //0!=1;
+      }
+      else  // show error if the user enters a negative integer
+      {
+        printf("Error! Factorial of a negative number doesn't exist.");
+      }
+      printf(" %d!= %llu\n", n, factorial);
+
+      break;
+
+   case(2):
+      printf("Enter an integer: ");
+      scanf("%d",&n);
+
+      if (n > 0){
+        for(i=n; i>=1; i-=2)
+        {
+            factorial *= i;  //n! = n*(n-1)...
+        }
+      }
+      else if( n = 0){
+        factorial = 1; //0!=1;
+      }
+      else  // show error if the user enters a negative integer
+      {
+        printf("Error! Double Factorial of a negative number doesn't exist.");
+      }
+      printf(" %d!!= %llu\n", n, factorial);
+
+      break;
+
+   case(3):
+       printf("Good bye!\n");
+
+      break;
+
+   default:
+       printf("Invalid number, please choose again.");
+   }
+
+}
+   return 0;
+}