别抄！有陷阱

解题思路 这道题考察的是我们对于循环的掌握。 我们需要通过循环来输出 废话不多说，我上答案了 答案 * 方法一 * 方法二 * 方法3 * 方法4 提问时间 大家尽情地提问吧，我会尽量的解答，并且筛选一些有用的及其回答放在此处哦！

#include<iostream> using namespace std; int main(){ int k,ans; cin>>k; for(int i=1;i<=k;i*=2) ans+=i; cout<<ans; }

#include <bits/stdc++.h> using namespace std; int main(){ int a,c=1,w=0;cin>>a; for(int i=1;i<=a;i++){ if(c>a){ break; } w+=c; c*=2; }cout<<w; return 0; }

#include<iostream> using namespace std; int main(){ int n; cin>>n; int sum = 0; for(int i=1;i<=n;i*=2){ sum+=i; } cout<<sum; return 0; }

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#include<bits/stdc++.h> using namespace std; int main(){ int n; cin>>n; int sum=1; int S=0; for(int i=1;i<=n;i++){ if(sum<=n){ S+=sum; sum*=2; }else{ cout<<S; return 0; } } return 0; }

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