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    <p>There are a couple of problems with your program.</p> <p>What you are doing is equivalent of:</p> <pre><code>char data[SIZE]; char *p; /* get some useful value in data */ p = data; </code></pre> <p>In <a href="https://stackoverflow.com/questions/2035066/type-of-an-array/2035255#2035255">the context of the last line</a>, <code>data</code> refers to a pointer that points to the first element of the array <code>data</code> (i.e., the line is equivalent to <code>p = &amp;data[0];</code>). So, what you just did was to assign to the pointer <code>p</code> the value of the address of the first character in <code>data</code>. Later, when you change the <em>contents</em> of <code>data</code>, the pointer to the first element of <code>data</code> is still the same (<code>data</code> still exists at the same memory location). So, all your pointers refer to the same storage, and you keep overwriting what's in the storage.</p> <p>But then why does your program work when you provide literal strings? Because each literal string in C is guaranteed to exist throughout the life of the program and has a unique address. (There is a minor exception: if you use a literal string more than once in your program, it may or may not refer to the same memory.)</p> <p>So, you should dynamically allocate memory for <code>firstName</code>, <code>lastName</code>, and <code>phoneNumber</code> members of your nodes, and remember to free them when you are done with it.</p> <pre><code>void addEntry(char *fn, char *ln, char *pn) { struct bookNode *tempNode, *iterator; tempNode = malloc(sizeof *tempNode); tempNode-&gt;firstName = malloc(strlen(fn) + 1); /* +1 for terminating 0 */ tempNode-&gt;lastName = malloc(strlen(ln) + 1); tempNode-&gt;phoneNumber = malloc(strlen(pn) + 1); /* Omitted check for malloc failures for brevity */ strcpy(tempNode-&gt;firstName, fn); strcpy(tempNode-&gt;lastName, ln); strcpy(tempNode-&gt;phoneNumber, pn); /* Now continue with what you were doing */ } </code></pre> <p>Then, you will need a corresponding <code>freeEntry</code> function to free up the space.</p> <p>Another way to do this would be to declare your <code>struct</code> differently:</p> <pre><code>#define MAX 20 struct bookNode { char firstName[MAX]; char lastName[MAX]; char phoneNumber[MAX]; struct bookNode *next; } *head; </code></pre> <p>Then, your <code>addEntry</code> function doesn't need the <code>malloc()</code> calls for <code>firstName</code>, <code>lastName</code>, and <code>phoneNumber</code>, but you still need to copy data using <code>strcpy()</code>. (To know the reason, please refer to the link above.) Your corresponding <code>freeEntry()</code> function also wouldn't need to free those members.</p> <p>Now, for the rest of your program. Your way of finding a terminating newline works, but you can simplify it by using <code>strchr()</code> standard C function. The call in your case would look like:</p> <pre><code>char *nl; if ((nl = strchr(first, '\n')) != NULL) { *nl = '\0'; } </code></pre> <p>Finally, when you fix all the above, you will find that you are getting the <a href="http://c-faq.com/stdio/feof.html" rel="nofollow noreferrer">last record twice</a> in your phone book. In C, <code>feof()</code> doesn't tell you if you are at the end of file now: it tells you that the last attempt to read from the file failed because you <em>were</em> at end of the file.</p>
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