langs a-z

Task/Happy-numbers/UNIX-Shell/happy-numbers.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+function sum_of_square_digits
+{
+  local -i n="$1" sum=0
+  while (( n )); do
+    local -i d=n%10
+    let sum+=d*d
+    let n=n/10
+  done
+  echo "$sum"
+}
+
+function is_happy?
+{
+   local -i n="$1"
+   local seen=()
+   while (( n != 1 )); do
+     if [ -n "${seen[$n]}" ]; then
+        return 1
+     fi
+     seen[n]=1
+     let n="$(sum_of_square_digits "$n")"
+   done
+   return 0
+}
+
+function first_n_happy
+{
+  local -i count="$1"
+  local -i n
+  for (( n=0; count; n+=1 )); do
+  if is_happy? "$n"; then
+    echo "$n"
+    let count-=1
+  fi
+  done
+  return 0
+}
+
+first_n_happy 8