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copied!<p>You can't - in C. In C initializing of global and local static variables are designed such that the compiler can put the values statically into the executable. It can't handle non-constant expressions as initializers. And only in C99, you can use non-constant expression in aggregate initializers - not so in C89! </p> <p>In your case, since your array is an array containing characters, each element has to be an arithmetic constant expression. Look what it says about those</p> <blockquote> <p>An arithmetic constant expression shall have arithmetic type and shall only have operands that are integer constants, ﬂoating constants, enumeration constants, character constants, and sizeof expressions.</p> </blockquote> <p>Surely this is not satisfied by your initializer, which uses an operand of pointer type. Surely, the other way is to initialize your array using a string literal, as it explains too</p> <blockquote> <p>All the expressions in an initializer for an object that has static storage duration shall be constant expressions or string literals.</p> </blockquote> <p>All quotes are taken out of the C99 TC3 committee draft. So to conclude, what you want to do - using non-constant expression - can't be done with C. You have several options: </p> <ul> <li>Write your stuff multiple times - one time reversed, and the other time not reversed. </li> <li>Change the language - C++ can do that all.</li> <li>If you <em>really</em> want to do that stuff, use an array of <code>char const*</code> instead</li> </ul> <p>Here is what i mean by the last option</p> <pre><code>char const c[] = "ABCD"; char const *f[] = { &c[0], &c[1], &c[2], &c[3] }; char const *g[] = { &c[3], &c[2], &c[1], &c[0] }; </code></pre> <p>That works fine, as an address constant expression is used to initialize the pointers</p> <blockquote> <p>An address constant is a null pointer, a pointer to an lvalue designating an object of static storage duration, or a pointer to a function designator; it shall be created explicitly using the unary & operator or an integer constant cast to pointer type, or implicitly by the use of an expression of array or function type. The array-subscript [] and member-access . and -> operators, the address & and indirection * unary operators, and pointer casts may be used in the creation of an address constant, but the value of an object shall not be accessed by use of these operators.</p> </blockquote> <p>You may have luck tweaking your compiler options - another quote:</p> <blockquote> <p>An implementation may accept other forms of constant expressions.</p> </blockquote>

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