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copied!<p>When you do</p> <pre><code>char* something = "a string literal"; </code></pre> <p>The compiler puts <code>"a string literal"</code> into the executable image itself and just assigns a pointer to this memory to <code>something</code>. You are not allowed to modify this memory, and many times the memory that the string resides in is marked read-only, so any attempts to write to it result in an access violation like the one you experienced.</p> <p>When you do </p> <pre><code>char something[] = "a string literal"; </code></pre> <p>you are really creating an array on the stack named <code>something</code> and <em>initialising</em> it with <code>"a string literal"</code>. This is equivalent of doing <code>char something[] = {'a', ' ', 's', 't', 'r', ..., 'a', 'l', 0};</code>. Since this memory is on the stack, you can modify it freely.</p> <p><code>char* something = "a string literal"</code> looks like</p> <pre><code> stack executable ------------- --------------------- |~~~~~~~~~~~| | ~~~~~~~~~~~~~~~~~ | | something | -----------------> | a string literal0 | ------------- | ~~~~~~~~~~~~~~~~~ | --------------------- </code></pre> <p>Whereas <code>char something[] = "a string literal"</code> looks like</p> <pre><code>stack ----- |~~~| | a | <- something is an alias for this location | | | s | | t | | r | | i | | n | | g | | | | l | | i | | t | | e | | r | | a | | l | | 0 | ----- </code></pre> <p>Where <code>~~~</code> means "other memory etc".</p> <p>Note that</p> <pre><code>char* x = "string literal"; </code></pre> <p>Is actually invalid and should not compile because you cannot convert a <code>char const[x]</code> to a <code>char*</code>. It should be <code>const char* x</code>, not <code>char* x</code>, but some old and non-conformant compilers wrongly allow this behaviour.</p>

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