#include<bits/stdc++.h> using namespace std; int n,a,x,s; int main(){ cin>>n; for(int i=1;i<=n;i++){ cin>>x; s=x; a=x/1%10; if(a<=4)cout<<s-a<<endl; if(a>=5)cout<<s-a+10<<endl; } return 0; }

直接用函数也可以

#include<bits/stdc++.h> using namespace std; int main(){ int n; cin >> n; int a[100]; for(int i=1;i<=n;i++){ cin >> a[i]; if(a[i]%10<5){ cout << a[i]-a[i]%10; cout << endl; } if(a[i]%10>=5){ cout << a[i]+(10-a[i]%10); cout << endl; } } return 0; }

#include<iostream> using namespace std; int main(){ int a,b,c; cin>>a; for(int i=1;i<=a;i++){ cin>>b; c=b%10; if(c<=4){ b=b/10*10; } else{ b=(b/10+1)*10; } cout<<b<<endl; } return 0; }