错误的：

#include<bits/stdc++.h> 
using namespace std;
int main(){
    int a,b,c,a1,b1,c1;
    cin>>a>>b>>c;
    if(a<=b && a<=c){
        a1=a;
        b1=b;
        c1=c;}
    else if(b<=a && b<=c){
        a1=b;
        b1=a;
        c1=c;
    }else{
    a1=c;
    b1=a;
    c1=b;}
    if(b1<=c1){
        cout<<a1<<" "<<b1<<" "<<c1;}
    else{
        cout<<a1<<" "<<c1<<" "<<b1;}
    return 0;
    }   

正确的：

#include<bits/stdc++.h>
using namespace std;
int main(){
	int a[3];
	for(int i=0;i<3;i++) scanf("%d",&a[i]);
	sort(a,a+3);
	for(int i=0;i<3;i++) printf("%d ",a[i]);
	return 0;
}