tasks a-s

Task/Perfect-numbers/Go/perfect-numbers.go

@@ -0,0 +1,36 @@
+package main
+
+import "fmt"
+
+// following function satisfies the task, returning true for all
+// perfect numbers representable in the argument type
+func isPerfect(n int64) bool {
+    switch n {
+    case 6, 28, 496, 8128, 33550336, 8589869056,
+        137438691328, 2305843008139952128:
+        return true
+    }
+    return false
+}
+
+// validation
+func main() {
+    for n := int64(1); ; n++ {
+        if isPerfect(n) != computePerfect(n) {
+            panic("bug")
+        }
+        if n%1e3 == 0 {
+            fmt.Println("tested", n)
+        }
+    }
+}
+
+func computePerfect(n int64) bool {
+    var sum int64
+    for i := int64(1); i < n; i++ {
+        if n%i == 0 {
+            sum += i
+        }
+    }
+    return sum == n
+}