Libcaptcha 是一个小型的可移植的用以生成 CAPTCHA 图片的 C 语言库，无需其他库的支持。    <br />    <pre class="brush:cpp; toolbar: true; auto-links: false;">const int gifsize; void captcha(unsigned char im[70*200], unsigned char l[6]); void makegif(unsigned char im[70*200], unsigned char gif[gifsize]);  int main() {         char l[6];         unsigned char im[70*200];         unsigned char gif[gifsize];          captcha(im,l);         makegif(im,gif);          write(1,gif,gifsize);         write(2,l,5);          return 0; }</pre>    <p><img alt="采用C语言CAPTCHA 图片 libcaptcha" src="http://static.open-open.com/lib/uploadImg/20111222/20111222142204_428.do" width="200" height="70" /></p>    <p><strong>项目主页：</strong><a href="http://www.open-open.com/lib/view/home/1324534929968" target="_blank">http://www.open-open.com/lib/view/home/1324534929968</a></p>