计算浮点数的n次方

计算浮点数的n次方，在北京大学的OJ网站上的题目，已经提交AC。可以作为参考。 原题如下： Description Problems involving the computation of exact values of very large magnitude and precision are common. For example, the computation of the national debt is a taxing experience for many computer systems. This problem requires that you write a