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    <p>In the case where <code>p="hello world";</code> (1st case at the time of this edit), <code>p</code> is being initialized to point to a <em>read-only</em> memory region which contains the string "hello world" (string literal). This <em>read-only</em> memory region is created at compile time.</p> <p>In the case that causes the segmentation fault (2nd case at the time of this edit), <code>p</code> is uninitialized and copying anything to it will produce unpredictable results because the location in memory that <code>p</code> is pointing to is not specified by the code.</p> <p>Before you can copy a string to <code>p</code>, you must specify the memory that <code>p</code> is pointing to. </p> <p>You can allocate this memory on the stack </p> <p><code>char buf[BUFSIZ] = ""; /* local variable */</code></p> <p>on the heap</p> <p><code>char *buf = malloc(BUFSIZ); /* don't forget to free */</code></p> <p>or in the __DATA segment.</p> <p><code>static char buf[BUFSIZ] = ""; /* global variable */</code></p> <p>You can then initialize <code>p</code> to point at the memory buffer.</p> <p><code>char *p = buf;</code></p> <p>This is similar in concept to initializing <code>p</code> to point to the string literal in <em>read-only</em> memory. Unlike the case where <code>p</code> points to the string literal, you can now copy a string to the character pointer as it does not point to <em>read-only</em> memory.</p> <p><strong>Note:</strong> I intentionally created a separate buffer and initialized <code>p</code> to point to it to help make my point.</p>
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    1. POWhy Can't we copy a string to Charater Pointer WHEN we can assign a string directly to it?
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    1. COThen, why would this work? #include <stdio.h> #include <string.h> int main() { char *p; p="hello world"; printf("p is %s \n",p); return 0; } <b>Output:</b> p is hello world
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    2. COYou aren't coping anything to p in the first one. You're assigning the address of that string literal to p. That's why it works.
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    3. COBy assigning the address of the string literal to p, you are specifying the location in memory that p is pointing to.
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