不用循环！！！

#include<iostream>
using namespace std;
int main(){
int a,b,c;
cin >> a >> b >> c;
if(a>b){
swap(a,b);
}
if(b>c){
swap(b,c);
}
if(a>b){
swap(a,b);
}
cout << a << " " << b << " " << c;
return 0;
}