#include<bits/stdc++.h> using namespace std; int main (){ /** 字符 char 数字 整数 int long long小数double float bool 0 1 true flase if() if(){}else{} if(){}else if(){}else{} if(){ if(){ } } for(){} do{}while while(条件){ } int sum=0; for(int i = 1;i<=5;i++){ sum+=i; } cout<<sum; //55 1-n 55 155 sum=0; int i=1; while(sum<=155){ sum+=i; i++; } int n,sum=0; cin>>n; while(n!=0){ sum+=n % 10; n = n /10; } cout<<sum; **/ int sum=0; int i=1; while(sum<=1000){ sum+=i; i++; } cout<<i-1; return 0; }