higher order function or def function including function-----------
<blockquote>
<blockquote>
<blockquote>
<blockquote>
the function which has input parameter as function..
or return function as output is Called Higher Order Function.
</blockquote>
</blockquote>
</blockquote>
</blockquote>
<pre><code>scala&gt; def Transform(x: Int, f(x): Int =&gt; Int) = {f(x)}
&lt;console&gt;:1:* error:* ':' expected but '(' found.
def Transform(x: Int, f(x): Int =&gt; Int) = {f(x)}
 ^

scala&gt; def Transform1(x: Int, f(x): Int =&gt; Int) = {f(x)}
&lt;console&gt;:1: *error:* ':' expected but '(' found.
def Transform1(x: Int, f(x): Int =&gt; Int) = {f(x)}
 ^

scala&gt; def Transform1(x: Int, f(x: Int) =&gt; Int) = {f(x)}
&lt;console&gt;:1: *error:* ':' expected but '(' found.
def Transform1(x: Int, f(x: Int) =&gt; Int) = {f(x)}
 ^
\\Correct One is..

scala&gt; def Transform1(x: Int, f: Int =&gt; Int): Int = {f(x)}
Transform1: (x: Int, f: Int =&gt; Int)Int

scala&gt; Transform1(12, square)
res2: Int = 144
</code></pre>Here Square is a function....
Transform1 is a Higher Order Function.

higher order function or def function including function-----------

>>>>the function which has input parameter as function..
or return function as output is Called **Higher Order Function.**



```
scala> def Transform(x: Int, f(x): Int => Int) = {f(x)}
<console>:1:* error:* ':' expected but '(' found.
def Transform(x: Int, f(x): Int => Int) = {f(x)}
 ^

scala> def Transform1(x: Int, f(x): Int => Int) = {f(x)}
<console>:1: *error:* ':' expected but '(' found.
def Transform1(x: Int, f(x): Int => Int) = {f(x)}
 ^

scala> def Transform1(x: Int, f(x: Int) => Int) = {f(x)}
<console>:1: *error:* ':' expected but '(' found.
def Transform1(x: Int, f(x: Int) => Int) = {f(x)}
 ^
\\Correct One is..

scala> def Transform1(x: Int, f: Int => Int): Int = {f(x)}
Transform1: (x: Int, f: Int => Int)Int

scala> Transform1(12, square)
res2: Int = 144
``` 

Here **Square ** is a function....

****Transform1 ****is a Higher Order Function.

Higher Order Function..