In this course, you'll study the fundamentals and principles of functional programming.

ocaml_utop_haskell.tar.gz

OCaml

Functional programming is a paradigm that builds complete applications by breaking down programs into constituent functions that empowers developers to build fast, bug-resistant applications.

You’ll be introduced to functional programming with illustrative examples contrasting the more widely used imperative programming paradigm. You’ll review lambda calculus as an introduction to expressions, the building blocks of functional programs. You’ll continue with abstractions and complex data types before exploring common computation patterns. Next, you’ll learn how dataflows create whole programs out of existing functions. Finally, you’ll finish by applying your functional programming knowledge to various real-world scenarios. At each step, you’ll learn OCaml and Haskell, while contrasting imperative programming with Java.

By the end of this course, you’ll be prepared to use functional programming in your daily work and have the framework to know when to use either imperative or functional paradigms.

Mastering Functional Programming with OCaml and Haskell

Functions such as 

```
square x = x * x
```

Variable assignments such as

```
c = c + 1
```

`for/while` loops such as

```java
for (int i = 0; i < n; i++) {
 c = c + 1
}

while (i < n) {
 c = c + 1
}
```

**(Select all that apply)** Which of the following typical language elements of imperative programming languages do not exist in functional programming languages?



(Select all that apply) Which of the following typical language elements of imperative programming languages do not exist in functional programming languages?

It is a boolean expression that evaluates to `false`

It increases the value of `x` by 1. So, `x` becomes `43`.

**(Select all that apply)** Given the following name declaration in OCaml, What does x = x + 1 do?

```
let x = 42
```


(Select all that apply) Given the following name declaration in OCaml, What does x = x + 1 do?
<pre><code>let x = 42
</code></pre>

**(Select all that apply)** For the input `if true then 42 else "Bye"`, the OCaml compiler gives the following error:

```ocaml
Error: This expression has type string but an expression was expected of type
         int
```

What kind of error is this?

(Select all that apply) For the input <code>if true then 42 else &quot;Bye&quot;</code>, the OCaml compiler gives the following error:
<pre><code class="language-ocaml">Error: This expression has type string but an expression was expected of type
 int
</code></pre>
What kind of error is this?

**(Select all that apply)** For the input, `if 00aa = 0 then "Hi" else "Bye"`, the OCaml compiler shows the following error:

```ocaml
Error: Invalid literal 00aa
```

What kind of error is this?

(Select all that apply) For the input, <code>if 00aa = 0 then &quot;Hi&quot; else &quot;Bye&quot;</code>, the OCaml compiler shows the following error:
<pre><code class="language-ocaml">Error: Invalid literal 00aa
</code></pre>
What kind of error is this?

**(Select all that apply)** What is the value of the following expression?

```ocaml
let s = if 42 mod 2 = 0 then "even" else "odd" in "The number is " ^ s

```

(Select all that apply) What is the value of the following expression?
<pre><code class="language-ocaml">let s = if 42 mod 2 = 0 then &quot;even&quot; else &quot;odd&quot; in &quot;The number is &quot; ^ s

</code></pre>

**(Select all that apply)** What is the type of the following expression?

```ocaml
let s = if 1 > 2 then "a" else "b" in (String.length s) > 0
```

Here, `String.length` is an OCaml function that returns the length of a string.

(Select all that apply) What is the type of the following expression?
<pre><code class="language-ocaml">let s = if 1 &gt; 2 then &quot;a&quot; else &quot;b&quot; in (String.length s) &gt; 0
</code></pre>
Here, <code>String.length</code> is an OCaml function that returns the length of a string.

**(Select all that apply)** Given the following OCaml code, what are the values of `a` and `b`?

```ocaml
let a = 42
let b = let a = 1 in a + 1
```

(Select all that apply) Given the following OCaml code, what are the values of <code>a</code> and <code>b</code>?
<pre><code class="language-ocaml">let a = 42
let b = let a = 1 in a + 1
</code></pre>

`if` is a statement and can not be used as an operand of the comparison operator.

**(Select all that apply)** Given the following imperative code in Java, why does the Java compiler reject this code?

```java
int x = 1;

if (x >= 0) {
   x + 1;
} > 2
```


(Select all that apply) Given the following imperative code in Java, why does the Java compiler reject this code?
<pre><code class="language-java">int x = 1;

if (x &gt;= 0) {
 x + 1;
} &gt; 2
</code></pre>

Introduction

Expressions: Building Blocks of Functional Programs

Building Abstractions with Functions

Compound Data Types

Common Computation Patterns

Dataflow Programming with Functions

Applying Functional Programming to Various Domains

Conclusion

Appendix

Quiz on Expressions