perfect number

DIRECTORY.md

@@ -201,6 +201,7 @@
   * [Lcm](https://github.com/TheAlgorithms/C/blob/HEAD/math/lcm.c)
   * [Lerp](https://github.com/TheAlgorithms/C/blob/HEAD/math/lerp.c)
   * [Palindrome](https://github.com/TheAlgorithms/C/blob/HEAD/math/palindrome.c)
+  * [Perfect Numbers](https://github.com/TheAlgorithms/C/blob/HEAD/math/perfect_numbers.c)
   * [Prime](https://github.com/TheAlgorithms/C/blob/HEAD/math/prime.c)
   * [Prime Factoriziation](https://github.com/TheAlgorithms/C/blob/HEAD/math/prime_factoriziation.c)
   * [Prime Sieve](https://github.com/TheAlgorithms/C/blob/HEAD/math/prime_sieve.c)

math/perfect_numbers.c

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <stdbool.h>
+#include <assert.h>
+#include <math.h>
+
+/* This function returns true 
+    if the submitted number is perfect,
+    false if it is not.
+
+    A perfect number is a positive integer that is
+    equal to the sum of its positive proper
+    divisors, excluding the number itself.
+
+    About perfect numbers: https://en.wikipedia.org/wiki/Perfect_number
+
+    @author Marco https://github.com/MaarcooC
+    @param int $number
+    @return bool */
+
+bool isPerfect(int number) {
+    // Handle edge cases: negative numbers and zero
+    if (number <= 1) {
+        return false; // 0 and negative numbers are not perfect
+    }
+
+    int sumOfDivisors = 1; // Initialize the sum of divisors with 1
+
+    // Check for divisors from 2 to sqrt(number)
+    for (int i = 2; i <= sqrt(number); i++) {
+        if (number % i == 0) { // If it is divisible
+            sumOfDivisors += i; // Add i to the sum of divisors
+            if (i != number / i) {
+                sumOfDivisors += number / i; // Add the corresponding divisor
+            }
+        }
+    }
+
+    return sumOfDivisors == number;
+}
+
+// tests
+void tests() {
+    assert(isPerfect(1) == false);
+    assert(isPerfect(6) == true);
+    assert(isPerfect(28) == true);
+    assert(isPerfect(-1) == false);
+    assert(isPerfect(0) == false);
+    assert(isPerfect(496) == true);
+}
+
+int main() {
+    tests();
+    printf("All tests passed!");
+    return 0;
+}