1.c

@@ -1,4 +1,15 @@
 #include <iostream>
+int factorial(int n) {
+    return (n == 1 || n == 0) ? 1 : n * factorial(n - 1);
+}
+int main() {
+    int num;
+    std::cout << "Enter a number: ";
+    std::cin >> num;
+    std::cout << "Factorial: " << factorial(num) << std::endl;
+    return 0;
+}
+#include <iostream>
 int sum(int a, int b) {
     return a + b;
 }