2-7调用POW函数求2^i的求和
![](http://images0.cnblogs.com/blog/570136/201310/20205119-2269c6a8ebbc4546ad68faaaf56519d2.png)
#include<stdio.h> #include<math.h> /*调用POW数学函数*/int main(void) { int n,i,power; double product; printf("Enter n:"); scanf("%d",&n); product=0; for(i=1;i<=n;i++){ power=pow(2,i); /*调用函数*/ printf("%d",power); product=product+power; /*求和*/ } printf("product=%.0f\n",product); return 0; }