答案

#include<bits/stdc++.h>

using namespace std; 

int main(){ 

int a; 

cin>>a; 

if(a<8){ 

cout<<"You are too young!"<<endl;

 } else if(a>=8&&a<=12){

 cout<<"Welcome to Junior Class!"<<endl;

 } else if(a>=13&&a<=18){

 cout<<"Welcome to Senior Class!"<<endl; 

} else{

     cout<<"You are too old!"<<endl;

 } 

return 0;

 }