dissarium number

math/dissarium_number.cpp

@@ -0,0 +1,48 @@
+#include <cmath>
+#include <iostream>
+#include <string>
+
+/*
+Check if a number is a Disarium number.
+
+A Disarium number is a number in which the sum of its digits
+powered with their respective positions is equal to the number itself.
+
+Args:
+    num (int): The number to check.
+
+Returns:
+    bool: true if num is a Disarium number, false otherwise.
+
+Examples:
+    is_disarium(135) -> true
+    is_disarium(89)  -> true
+    is_disarium(75)  -> false
+    is_disarium(9)   -> true
+*/
+bool is_disarium(int num) {
+    std::string digits = std::to_string(num);
+    int total = 0;
+    int position = 1;
+
+    for (char c : digits) {
+        int digit = c - '0';  // convert char to int
+        total += std::pow(digit, position);
+        position++;
+    }
+
+    return total == num;
+}
+
+int main() {
+    // Test examples
+    int test_numbers[] = {135, 89, 75, 9};
+    for (int n : test_numbers) {
+        std::cout << n << " is "
+                  << (is_disarium(n) ? "a Disarium number"
+                                     : "not a Disarium number")
+                  << std::endl;
+    }
+
+    return 0;
+}