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    <p>You want the comfort of named fields (<code>bar1</code> .. <code>barN</code>) and something like an array you can loop over to automate the operations. First we define the struct (a dense representation of the fields in memory):</p> <pre><code>struct VectorFields { int a; int b; int c; }; </code></pre> <p>Then we need to get to know the number of the fields used in that struct:</p> <pre><code>#define VECTOR_FIELDS_LEN (sizeof(struct VectorFields) / sizeof(int)) </code></pre> <p>(In C++ you could use some template magic foo, here we just use the preprocessor as a simpler variant). Next, we combine the <code>struct VectorFields</code> with an array of <code>int</code> so both match in size, also known as <code>union</code>:</p> <pre><code>union Vector { struct VectorFields fields; int raw[VECTOR_FIELD_LEN]; }; </code></pre> <p>(Note: <code>VECTOR_FIELD_LEN</code> must be a known constant value to the compiler, hence the preprocessor thingy before.) You are now able to access the data either by it's name (<code>.fields.a</code>) or by an index (<code>.raw[0]</code>). So, let's write the function which adds the <code>Vector</code> together:</p> <pre><code>void vector_add(union Vector* result, union Vector* a, union Vector* b) { int i; for (i = 0; i &lt; TUPLE_LEN; i++) { result-&gt;raw[i] = a-&gt;raw[i] + b-&gt;raw[i]; } } </code></pre> <p>You might use it like this then:</p> <pre><code>#include &lt;stdio.h&gt; int main() { union Vector a = { .fields = { 1, 2, 3 } }; union Vector b = { .fields = { 4, 5, 6 } }; union Vector sum; vector_add(&amp;sum, &amp;a, &amp;b); printf("%d %d %d\n", sum.fields.a, sum.fields.b, sum.fields.c); return 0; } </code></pre>
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    1. POAdding (or doing any other math) every member of two same structs with less code
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    1. COExplanation? This is not a trivial one-liner.
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    2. COIt's a union between a structure and an array. Wow. Does it work only on a structure with only one member type?
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    3. COWhy shouldn't it? @Zupoman
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