<code><span class="hljs-meta">#<span class="hljs-meta-keyword">include</span> <span class="hljs-meta-string"><stdio.h></span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">include</span> <span class="hljs-meta-string"><math.h></span></span>
<span class="hljs-meta">#<span class="hljs-meta-keyword">define</span> PI 3.141592654</span>

<span class="hljs-function"><span class="hljs-keyword">int</span> <span class="hljs-title">main</span><span class="hljs-params">()</span>
</span>{
   <span class="hljs-keyword">double</span> arg = <span class="hljs-number">30</span>, result;

   <span class="hljs-comment">// Converting to radian</span>
   arg = (arg * PI) / <span class="hljs-number">180</span>;
   result = <span class="hljs-built_in">cos</span>(arg);

   <span class="hljs-built_in">printf</span>(<span class="hljs-string">"cos of %.2lf radian = %.2lf"</span>, arg, result);

   <span class="hljs-keyword">return</span> <span class="hljs-number">0</span>;
}</code>