#include <iostream> using namespace std; int main() { int sum=1; for(int a=1;a<=8;a+=1)//yufen sum=sum*2; //sum 1 sum = sum * 2 = 2 sum = sum * 2 = 2 * 2=4 sum * 2 = 4 * 2 = 8 cout<<sum; return 0; }