$1$ Purpose

The high$-$level goal of this assignment is to help you build up a mental model of what is happening inside the machine when your code is executed. You will gain experience with several key aspects of $C$ and system programming:

Implementing a utility independent of any particular application progam $($i$.$e$.,$ you will not write, and must not assume anything about the main program$),$ and designing and implementing test cases for your implementation.

Using pointers in data structures, both in general and in storing string $($character sequence$)$ values.

Dynamic memory management, using malloc and free.

Separate compilation units.

$2$ Overview

A hash map $($or hash table$)$ is a data structure that stores key$-$value pairs. That is$,$ the programming interface to the data structure provides two primary methods:

Bind a value $($usually of a particular type$)$ to a particular key, which is always a value of a particular type.

Get the value bound to a given key, if any.

Thus a hash map acts like an associative array. Many high$-$level programming languages offer similar data abstractions as a built$-$in facility; C does not. Names referring to such abstractions are "map", "dictionary" and "key$-$value store". Our implementation approach will yield $($approximately$)$ constant access time, provided the usage pattern satisfies certain assumptions.

For this assignment, the keys will be C strings $($null$-$terminated arrays of char$),$ and values will be of type void $*.$ The latter type is used in C as a generic "container" for pointer values when their type